This study develops a volatile fingerprinting approach for authenticating traditional sesame oil using HS-SPME-GC-MS with GC×GC-MS-assisted compound identification. Conventional GC-MS fingerprints were evaluated by similarity analysis, while GC×GC-MS improved identification of volatile markers in authentic and adulterated samples.The method detected maize oil dilution at levels as low as 5% and sesame oil essence adulteration from 0.2%. Principal component analysis and sensory evaluation supported the fingerprint-based classification, demonstrating a reproducible strategy for detecting different types of sesame oil adulteration.<blockquote><h4>The original article</h4><h4><a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#sec0010">Volatile compound fingerprinting for traditional sesame oil authentication using GC-MS with GC×GC-MS-assisted identification&nbsp;</a></h4>Ruibing Jin, Fuyun Kuang, Qi Meng, Lijin Wang, Huanlu Song, Xueping Feng, Mingshan ZouJournal of Food Composition and Analysis, 2026, 155:109277<div><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1016/j.jfca.2026.109277">https://doi.org/10.1016/j.jfca.2026.109277</a></div><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/">CC-BY 4.0</a></h6></blockquote>Selected sections from the article follow. Formats and hyperlinks were adapted from the original.<div><div><div><div><div>Sesame is cultivated worldwide for its nutritional value and flavor, especially in India, China, Myanmar, and Tanzania (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib23">Yin et al., 2021</a>). Sesame oil (SO) is an edible oil made from sesame seeds roasted at high temperatures to produce the distinct aroma and then processed using pressing, leaching, or other methods (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib5">Huang et al., 2024</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib11">Ma et al., 2022</a>). This traditional Chinese characteristic edible oil is extremely popular among consumers because of its high nutritional value and unique flavor. The unique aroma is an important indicator of quality and the main feature that distinguishes SO from other vegetable oils. SO contains fatty acids, vitamin E, and phytosterols that support cardiovascular health and anticarcinogenic processes (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib21">Xu et al., 2025</a>), along with sesamin and other lignans that impart strong antioxidant and anti-corticosteroid properties (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib24">Yin et al., 2024</a>). Owing to its nutritional and sensory values, the high retail price of SO has motivated adulteration with cheaper edible oils or SO essences (SOE). Therefore, the development of SO adulteration detection technologies such as fingerprinting is essential.Fingerprinting technology typically involves using analytical detection and data processing methods to generate chromatograms/spectra of the separate sample components simultaneously. In China, fingerprinting is primarily used in the fields of traditional Chinese medicine, biology, and food production. To ensure the quality of traditional Chinese medicines, the Chinese Pharmacopoeia Commission developed the “Chinese Medicine Chromatographic Fingerprint Spectra Similarity Evaluation System” (Fingerprint Similarity System). After importing sample chromatograms, the software generates a reference fingerprint spectrum based on the retention times and peak heights, from which the similarity between the individual samples and reference spectrum is calculated. Samples with similarities &gt; 0.900 are considered highly compatible with the reference fingerprint (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib13">National Medical Products Administration, 2000</a>). Chromatographic fingerprinting is particularly valuable for traditional SOs and reveals how variations in raw material origin or production processes influence the overall similarity of the volatile component profiles across samples. This enables more effective adulteration detection, origin discrimination, varietal differentiation, and characteristic substance analysis (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib3">Fu et al., 2023</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib14">Shi et al., 2025</a>; <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib15">Sun et al., 2023</a>).Volatile compound fingerprinting has been employed to characterize the volatile profiles of food products, enabling product discrimination and quality assessment (including identification and grading). <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib16">Sun et al. (2020)</a> analyzed volatile flavor compounds in SO and SO adulterated with soybean oil and identified characteristic compounds that can serve as indicators for adulteration. <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib18">Wang et al. (2024a)</a> used UV spectral fingerprints in combination with chemometric analytical methods to assess the quality of pressed SO with different levels of adulteration with refined SO. <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib1">Aghili et al. (2023)</a> analyzed the fatty acid compositions of diluted SO samples using an electronic nose (e-nose) and gas chromatography-mass spectrometry (GC-MS), revealing differences in the volatile profiles between the original and adulterated SO samples, which could aid in distinguishing adulterations. <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib20">Xing et al. (2019)</a> established fatty acid fingerprints capable of identifying sesame oil adulterated with rapeseed oil at levels as low as 5%. However, the sensitivity decreased for adulteration with corn oil, where only levels above 10% were detectable. Although <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib26">Zhang et al. (2016)</a> established a simple and rapid ion mobility spectrometry method to identify sesame oil adulterated with flavoring substances, its detection capability is limited to adulteration levels above 10%. However, few studies have assessed the performance of GC-MS-based fingerprinting in the concurrent detection of SO dilution and essence adulteration from volatile profiles.Although the chromatographic fingerprint similarity evaluation system was originally developed for traditional Chinese medicines, it has recently been successfully applied to edible oils. For example, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib7">Li et al. (2025)</a> established volatile fingerprints for fried pepper oils using the "Chinese Medicine Chromatographic Fingerprint Similarity Evaluation System" and adopted a similarity threshold of 0.900 for quality discrimination. Therefore, we characterized the volatile fingerprint of authentic traditional SO using headspace solid-phase microextraction (HS-SPME) coupled with two-dimensional GC (GC×GC)-MS; co-elution issues were resolved by parallel GC×GC-MS analysis, while fingerprint similarity was evaluated using the "Chinese Medicine Chromatographic Fingerprint Similarity Evaluation System" based on GC-MS data. By comparing this fingerprint with those of diluted SO by maize oil (MO) and sesame essence-adulterated oil, we investigated the accuracy of the fingerprint model. This study provides a scientific basis for quality control and authentication of traditional SO.<h4>2. Materials and methods</h4><h5>2.4. GC×GC-MS</h5>GC-MS (<a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/gcms/library?mainauthorItems=10&amp;search=8890">8890</a>–<a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/gcms/library?mainauthorItems=10&amp;search=5977B">5977B</a>, Agilent Technologies, Santa Clara, CA, USA) with a solid-state modulator (SSM) 1800 (J&amp;X Technologies, Shanghai, China) was used to qualitatively analyze the volatile compounds of SO (B. <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib17">Wang et al., 2023</a>).Volatile compounds were detected as previously described (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib2">Duan et al., 2025</a>), with some modifications. Mass spectra were acquired over the range of 40–450 m/z. Ultra-purity helium (99.999% purity) served as the carrier gas, flowing at a rate of 1.2 mL/min. A splitless injection mode was used. The oven temperature program was set to 40 °C and held this temperature for 2 min, slowly increased to 230 °C at 4 °C per min, and held at 230 °C for 5 min. The detector temperature was set to 250 °C. The quadrupole temperature and transfer line temperature were 150 °C and 250 °C, respectively. An electron impact ion source with an electron energy of 70 eV was used. The ion source temperature was set to 230 °C. A full scan mode was applied for acquisition. Two columns were used inside the GC oven: the first was a polar column, DB-wax (30 m × 0.25 mm × 0.25 μm; Agilent Technologies); the second was a mid-polar column, DB−17 (mid-polar, 1.85 m × 0.18 mm × 0.18 μm; J&amp;X Technologies). SSM1800 was placed between them for the heating and cooling stages. The SSM modulation period was 4 s. GC×GC-MS was used solely for qualitative confirmation of compounds that co-eluted in GC-MS.<h5>2.5. GC-MS</h5>Volatile compounds were analyzed semi-quantitatively by GC-MS (<a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/gcms/library?mainauthorItems=10&amp;search=7890A">7890A</a>−<a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/gcms/library?mainauthorItems=10&amp;search=7000B">7000B</a>; Agilent Technologies), and 2-methyl−3-heptanone was used as an internal standard. GC-MS analysis was performed using a DB-wax column (polar, 30 m × 0.25 mm, 0.25 μm; Agilent Technologies, Folsom, CA, USA) to distinguish the volatile compounds. The carrier gas (ultra-pure helium, 99.999%) was delivered at a flow rate of 1.2 mL/min. The method, heating, and mass spectrometry conditions are consistent with those described in Section 2.4. All quantitative and fingerprint similarity analyses were based on the GC-MS data obtained from this section.<h4>3. Results and discussion</h4><h5>3.2. Analysis of volatile compounds</h5>The GC×GC-MS result of JH and the GC-MS results of JH, MSO 5 (50% MO), and MSE 3 (0.6% SOE) are shown in <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#fig0005">Fig. 1</a>. A total of 85 volatile compounds were identified in the SO, MSO, and MSE samples, and 33 common peaks were identified, including ketone (1), acid (1), nitrogen-containing compounds (16), sulfur-containing compounds (7), furans (3), aldehyde (1), and phenolic compounds (4, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#tbl0015">Table 3</a>).<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Journal_of_Food_Composition_and_Analysis_2026_155_109277_Fig_1_A_and_B_respectively_represent_the_three_dimensional_chromatogram_and_two_dimensional_chromatogram_336c1e9b86.jpg" alt="Journal of Food Composition and Analysis, 2026, 155:109277: Fig. 1. (A) and (B) respectively represent the three-dimensional chromatogram and two-dimensional chromatogram of volatile compounds within the JH−1 sesame oil sample; (C)-(E) respectively represent the GC-MS results of volatile compounds within the JH−1, MSO 6 (50% MO), and MSE 3 (0.6% MSE)." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Journal_of_Food_Composition_and_Analysis_2026_155_109277_Fig_1_A_and_B_respectively_represent_the_three_dimensional_chromatogram_and_two_dimensional_chromatogram_336c1e9b86.jpg 119w," sizes="100vw" width="1600" height="2107"><h5>3.3. Establishment of GC-MS fingerprints and similarity analysis of volatile substances</h5>The GC-MS volatile compound data from the test SO samples were imported into the Fingerprint Similarity System to generate chromatographic fingerprints. The reference fingerprint profile was constructed as the arithmetic mean of all profiles (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#fig0015">Fig. 3</a>). Similarity values between the sample fingerprints and reference were calculated to evaluate compositional consistency. The SO samples showed a reference fingerprint similarity of 0.910–0.993 (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#tbl0020">Table 4</a>), surpassing the 0.900 benchmark (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib10">Ma et al., 2024</a>). This demonstrates a consistent composition of key volatile components across samples with minimal quality variation, satisfying the fundamental fingerprinting and quality assessment requirements for traditional SO.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Journal_of_Food_Composition_and_Analysis_2026_155_109277_Fig_3_Reference_fingerprint_of_volatile_compounds_b17f79ad1a.jpg" alt="Journal of Food Composition and Analysis, 2026, 155:109277: Fig. 3. Reference fingerprint of volatile compounds in traditional SO established by GC-MS. Different numbers are represented the different compounds in Table 2." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Journal_of_Food_Composition_and_Analysis_2026_155_109277_Fig_3_Reference_fingerprint_of_volatile_compounds_b17f79ad1a.jpg 245w," sizes="100vw" width="1600" height="584"><h4>4. Conclusion</h4>This study established a volatile compound fingerprinting method using HS‑SPME‑GC‑MS with GC×GC‑MS‑assisted identification for the authentication of traditional sesame oil. A total of 33 common volatile peaks were identified, with pyrazines and guaiacol as major contributors. OPLS‑DA models (R²Y &gt; 0.98, Q² &gt; 0.97) demonstrated robust discrimination between authentic and adulterated oils, as well as between the two adulteration types. Compounds with VIP &gt; 1 and p &lt; 0.05 were identified as potential key markers. Selected key markers were then subjected to external standard quantification, and the obtained absolute concentrations were used to perform PCA. All calibration curves showed excellent linearity (R² &gt; 0.997), and the external standard PCA clearly separated sesame oil essence from all other samples. Fingerprint similarity analysis, validated by ROC (AUC = 1.000, optimal cutoff 0.8935), showed that adulterated samples had similarity values below 0.9, clearly distinguishing them from authentic oils. The method successfully detected maize oil dilution adulteration as low as 5% and sesame oil essence adulteration as low as 0.2%.Compared with previous methods (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib1">Aghili et al., 2023</a>; <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib18">Wang et al., 2024a</a>; <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib20">Xing et al., 2019</a>; <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0889157526004205#bib26">Zhang et al., 2016</a>), our approach uniquely detects both dilution and essence adulteration in a single workflow, achieves lower detection limits (5% for MO, 0.2% for SOE), and provides an intuitive 0.900 similarity threshold without complex chemometric modeling. While non‑destructive methods (e‑nose, IMS) are more suitable for rapid screening, our approach offers higher chemical specificity, the ability to distinguish between dilution and essence adulteration, and an intuitive similarity threshold. Current limitations include testing only maize oil and one essence type, and validation on laboratory‑prepared samples. Future work will expand to other adulterants (soybean, rapeseed oil) and blind commercial samples. Overall, this method provides a reproducible, empirically validated tool for traditional sesame oil authentication. Furthermore, external standard quantification in the present study was performed only for a selected set of key volatile markers (VIP&nbsp;&gt;&nbsp;1 and p&nbsp;&lt;&nbsp;0.05). The same approach can be extended to other compounds in future studies, enabling odor activity value (OAV) calculations for deeper insights into sensory contributions, more precise adulteration level prediction, and improved model robustness across different production batches.</div></div></div></div></div>

Volatile compound fingerprinting for traditional sesame oil authentication using GC-MS with GC×GC-MS-assisted identification

Comprehensive investigation of matrix effect evaluation approaches for reliable quantification in bioanalysis using UHPLC-MS/MS

This study compares loss-on-ignition, acid decarbonation, and combustion elemental analysis for measuring organic carbon in sediments using certified reference materials and real samples. Loss-on-ignition conversions were inaccurate, while acid washing before elemental analysis caused significant organic carbon loss and poor precision.Combustion pretreatment followed by elemental analysis provided accurate and precise organic and inorganic carbon measurements, confirmed by temperature-dependent combustion. Across more than 150 intertidal sediment samples, acid decarbonation underestimated organic carbon by 37% ± 8%, supporting combustion-based elemental analysis as the preferred approach for reliable sediment carbon determination.<blockquote><h4>The original article</h4><h4><a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#s0055">Comparing loss-on-ignition, acid decarbonation and combustion elemental analysis for measuring organic carbon concentrations – recommendations for best practice</a></h4>Robert B. Sparkes, Stuart A. Rae, Lucy McMahon, Hannah L. Mossman, David McKendry, Clare E. Dean, Graham Tinsley, Frances Fowden, Connor J. Grisdale, Hafiza Begum, Holly Hope, Charlotte McEnhill, Samuel O’Boyle, Nawal Sohail, Marvyn Wachira, Rachel M. DunkOrganic Geochemistry, Volume 218, 2026, 105215<div><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1016/j.orggeochem.2026.105215">10.1016/j.orggeochem.2026.105215</a></div><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/">CC-BY 4.0</a></h6></blockquote>Selected sections from the article follow. Formats and hyperlinks were adapted from the original.<div><div><div><div><div>Environmental and Earth scientists frequently require measurements of carbon contents, including both the total carbon concentration (TC) and the fractions contributed by carbon from organic matter (organic carbon; OC) and carbonate minerals (inorganic carbon; IC; <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0025">Bendle et al., 2009</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0220">Radabaugh et al., 2018</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0230">Saderne et al., 2019</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0240">Scheingross et al., 2019</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0260">Smeaton et al., 2021</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0295">Vonk et al., 2012</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0315">Wood et al., 2021</a>).Accurate, precise, and affordable carbon concentration measurements are critical to the drive towards net-zero emissions, which requires monitoring, reporting and verification of carbon burial and release from an array of global environments (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0210">Post et al., 2001</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0265">Smith, 2004</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0270">Smith et al., 2020</a>). Carbon concentration measurements also underpin further analyses (e.g. normalising the concentration of individual biomarker compounds against the total organic carbon concentration, calculating elemental carbon to nitrogen ratios (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0290">van Dongen et al., 2008</a>), determining the correct sample load for isotope ratio measurements). Despite carbon concentration measurements being ubiquitous throughout multiple disciplines there is no standard approach for making these, especially determining the organic component of the sedimentary carbon (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0080">Fest et al., 2022</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0320">Young et al., 2018</a>). Different disciplines have often generated their own consensus approach, which may not align with studies from another field, even those working on similar samples and asking similar questions (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0070">Farmer et al., 2014</a>). Use of an agreed standard measurement protocol for carbon concentrations, or understanding the agreement/variability between protocols, is vital for regulatory monitoring, reporting and verification (MRV), such as the ongoing development of carbon offsetting standards that, if implemented robustly, could provide real-world benefits to climate mitigation (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0035">Bonn et al., 2014</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0045">Burden et al., 2023</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0105">Guizar-Coutiño et al., 2022</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0190">Needelman et al., 2018</a>, <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0205">Pan et al., 2022</a>). Determining a standardised, verified approach to carbon measurement is important for those performing MRV, who may not have access to advanced and/or expensive analytical instrumentation.This study compares three common methods for quantifying the total and organic carbon concentrations in sedimentary samples: i) loss-on-ignition, ii) elemental analysis combined with acid decarbonation, and iii) elemental analysis combined with organic matter combustion. The comparison focuses on assessing the accuracy, precision, and repeatability of each method, identifying their respective strengths and weaknesses, and independently confirming findings via a fourth method (temperature dependent combustion and infrared CO2 measurement) to provide recommendations for best practice. A summary review of these methods is provided below.<h4>2. Materials and methods</h4><h5>2.3. Independent testing of reference materials via TDC</h5>Standards were analysed by the supplier (Elemental Microanalysis Ltd, UK) as part of the certification process: 15/30 elemental analysis measurements gave expected values of TC, OC and IC and the uncertainty for TC, following ISO/IEC17025. These values were independently checked using an <a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/icpms/library?mainauthorItems=16&amp;search=Soli+TOC">Elementar SoliTOC cube</a> instrument at the instrument manufacturer’s headquarters (Elementar Analysensysteme, Hanau, Germany), which used the TDC method. Two combustion ramps were applied, first a two-step OC and IC determination at 500 °C and 900 °C, and then a three-step programme at 400 °C and 600 °C for easily-combustible and residual OC fractions and 900 °C for IC, with three repeat measurements of each. The SoliTOC cube instrument also analysed the agricultural soil sample, again making three repeat measurements of both the two-step and three-step temperature dependent combustion protocols (see Supplementary Table 3).<h5>2.5. Elemental analysis</h5>Total carbon concentrations were measured following the protocol described in <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0180">Mossman et al. (2022)</a>. 20&nbsp;mg of either untreated or pre-treated sample was weighed into tin capsules (Elemental Microanalysis Ltd.) and analysed for carbon concentrations using a Vario EL cube elemental analyser (Elementar Ltd.). Before each analytical run, the instrument was cleaned using three blanks without oxygen and seven blanks with oxygen, and calibrated using five analyses of up to 14&nbsp;mg ethylenediaminetetraacetic acid (EDTA) standard (Elemental Microanalysis Ltd.) and three analyses of an independent Soil Standard (Clay) CRM, acquired separately to the Soil Standard (Clay) CRM used to create analytical samples for this study (Elemental Microanalysis Ltd.). Three analyses of the EDTA calibration standard were repeated after every twenty samples. Long-term drift was monitored by repeated measurements of an internal laboratory standard sample, which has been analysed since 2015. Over the course of 65 measurements across 10 instrument runs for this study the laboratory standard showed no systematic drift.<h4>3. Results and discussion</h4><h5>3.1. Testing of certified reference materials (CRMs) using temperature dependent combustion (TDC)</h5>Both two-step and three-step TDC protocols consistently measured carbon contents close to but slightly below the supplier-certified values (see <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#f0005">Fig. 1</a>). For Soil Standard (Clay), the TDC instrument under-estimated OC by 0.10&nbsp;wt% (two-step) and 0.14&nbsp;wt% (three-step) and IC by 0.15&nbsp;wt% (two-step) and 0.087&nbsp;wt% (three-step). For Soil Standard (Peaty) the TDC instrument underestimated OC by 0.26&nbsp;wt% (two-step) and 0.34&nbsp;wt% (three-step), and IC by 0.021&nbsp;wt% (two-step) and 0.090&nbsp;wt% (three-step). Relative differences for OC are small, 5.1 – 7.0% for Clay and just 1.7 – 2.2% for Peaty, but higher for IC due to the small amount of IC present in the standards (25 – 44% for Clay, 7.0 – 30% for Peaty).<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Organic_Geochemistry_Volume_218_2026_105215_Fig_1_Comparison_of_organic_carbon_and_inorganic_carbon_measurements_on_two_certified_reference_materials_using_four_methods_31537717b3.jpg" alt="Organic Geochemistry, Volume 218, 2026, 105215: Fig. 1. Comparison of organic carbon and inorganic carbon measurements on two certified reference materials using four methods. Upper panel is Soil Standard (Clay) and lower panel Soil Standard (Peaty). Yellow diamonds show the certified value (Elemental Microanalysis Ltd) with manufacturer stated uncertainty in total carbon used as error bars for OC and IC (n = 30). White and grey symbols represent Loss-on-Ignition results using four different organic matter to organic carbon conversion equations (grey sqaures use the “van Bemmelen” scaling factor (Pribyl, 2010), grey circles the Craft et al. (1991) factor, white diamonds the Ouyang and Lee (2020) equation and white circles the Smeaton et al. (2022) equation. IC values for all LoI results use the C/CO2 mass fraction (Wang et al., 2011). Blue circles show the acid decarbonation and elemental analysis protocol, orange circles the combustion and elemental analysis protocol. Green and purple circles show mean results from temperature dependent combustion method (2-step and 3-step protocols respectively). Error bars represent one standard deviation after multiple measurements (n = 2 to n = 4). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Organic_Geochemistry_Volume_218_2026_105215_Fig_1_Comparison_of_organic_carbon_and_inorganic_carbon_measurements_on_two_certified_reference_materials_using_four_methods_31537717b3.jpg 116w," sizes="100vw" width="2756" height="3698"><h5>3.4. Reproducibility tests</h5>Having shown that combustion coupled with elemental analysis was the most robust method for measuring OC in pure and diluted standards, the next experiment tested the reproducibility of these protocols over multiple implementations. A dried, ground agricultural soil sample was repeatedly analysed using each method (separate aliquots were measured using LoI at 500 °C and 800 °C, separate untreated aliquots were analysed via EA, separate aliquots were combusted at 500 °C and analysed via EA, and separate acid decarbonations were carried out prior to EA measurements). This required a large amount of starting material, more than was available in the CRMs. Independent external measurement of the soil sample using temperature dependent combustion (Elementar, Germany) gave mean OC&nbsp;=&nbsp;2.50&nbsp;±&nbsp;0.002&nbsp;wt% and IC&nbsp;=&nbsp;1.29&nbsp;±&nbsp;0.008&nbsp;wt% for combustion to 500 °C (n&nbsp;=&nbsp;3), whereas combustion to 600 °C gave OC&nbsp;=&nbsp;2.52&nbsp;±&nbsp;0.075 and IC&nbsp;=&nbsp;1.12&nbsp;±&nbsp;0.010&nbsp;wt% (n&nbsp;=&nbsp;3).<div>LoI showed differences in mean OC depending on the equation chosen (<a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#f0010">Fig. 2</a>). The conversions of <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0050">Craft et al. (1991)</a> and <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0200">Ouyang and Lee (2020)</a> were similar to the independent measurements (2.90&nbsp;±&nbsp;0.05&nbsp;wt% and 2.60&nbsp;±&nbsp;0.07&nbsp;wt% respectively; n&nbsp;=&nbsp;9 for each), but the equations of <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#b0255">Smeaton et al. (2022)</a> and van Bemmelen over-estimated OC (4.19&nbsp;±&nbsp;0.05 and 4.21&nbsp;±&nbsp;0.08&nbsp;wt% respectively; n&nbsp;=&nbsp;9 for each). IC estimates using the C/CO2 mass fraction conversion were higher than the expected value (1.91&nbsp;±&nbsp;0.06&nbsp;wt%, n&nbsp;=&nbsp;9). Note that the relative standard deviation for OCLoI was&nbsp;∼&nbsp;1.8%, and 3.2% for ICLoI, showing acceptable run-to-run precision.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Organic_Geochemistry_Volume_218_2026_105215_Fig_2_Organic_and_inorganic_carbon_measurements_following_repeated_analysis_of_a_homogenised_soil_sample_via_multiple_methods_c5d62ece0b.jpg" alt="Organic Geochemistry, Volume 218, 2026, 105215: Fig. 2. Organic and inorganic carbon measurements following repeated analysis of a homogenised soil sample via multiple methods. Markers for each method are shown in the legend and are the same as Fig. 1. Small black circles and error bars show the mean and one standard deviation after multiple repetitions of each protocol (n = 9 for LoI, C-EA and AD-EA, n = 3 for TDC)." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Organic_Geochemistry_Volume_218_2026_105215_Fig_2_Organic_and_inorganic_carbon_measurements_following_repeated_analysis_of_a_homogenised_soil_sample_via_multiple_methods_c5d62ece0b.jpg 204w," sizes="100vw" width="2363" height="1815">Since OCC-EA and ICAD-EA were calculated by subtraction from mean TCEA, all data from the C-EA and AD-EA methods plotted on a straight line in <a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0146638026000902#f0010">Fig. 2</a>, representing OC&nbsp;+&nbsp;IC&nbsp;=&nbsp;TC. However, position and scatter along that line varied between the two pre-treatment techniques. OCC-EA clustered just higher than the independent measurements using TDC (2.60&nbsp;±&nbsp;0.03&nbsp;wt%, n&nbsp;=&nbsp;9). Propagating the errors in TC and IC gave a combined error estimate of&nbsp;±&nbsp;0.1&nbsp;wt% for the repeated OCC-EA measurements. ICC-EA was also close to but slightly higher than the TCD results, 1.35&nbsp;±&nbsp;0.03&nbsp;wt%. AD-EA, however, gave mean OC values of 2.00&nbsp;±&nbsp;0.12&nbsp;wt% (n&nbsp;=&nbsp;9) which was more variable run-to-run than the other methods and gave a significantly (p&nbsp;&lt;&nbsp;0.0001) lower mean OC value than the TCD results. Once again, acid decarbonation results suggested that a large amount of organic matter was lost during the acid treatment, tested further in the next section.</div><h4>4.3. Conclusions</h4>An accurate, precise, efficient, and standardised method for measuring total, organic and inorganic carbon contents of sediment samples is critical for both scientific research and environmental monitoring and reporting and verification. We rigorously tested three methods for measuring carbon contents in soils and intertidal sediments, using certified reference materials and&nbsp;&gt;&nbsp;150 sediment samples. Loss-on-ignition (LoI) is cheap and easy but showed moderate run-to-run variability and, without careful calibration, it is not accurate.Elemental analysis (EA) is an accurate and precise method for total carbon (TC) analysis. Measuring organic and inorganic carbon via EA requires pre-treatment of the sample, and this study tested both acid decarbonation and combustion preparation techniques. Acid decarbonation led to significant and variable organic carbon loss, meaning that true organic carbon concentrations are likely higher than those measured following acidification. Combustion pre-treatment was shown to efficiently remove organic matter, leading to accurate and precise results, and we would recommend making organic carbon measurements in this way.</div></div></div></div></div>

Comparing loss-on-ignition, acid decarbonation and combustion elemental analysis for measuring organic carbon concentrations – recommendations for best practice

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KNAUER Eurospher II 100 C8 & C8A (U)HPLC Columns (USP L7)

C8 is a silica gel based stationary phase in reversed phase mode with alternative selectivity compared to C18 phases. 

Classical and hydrophilic/aqueous C8 columns for HPLC and UHPLC (USP L7)C8 is a silica gel based stationary phase in reversed phase mode with alternative selectivity compared to C18 phases. Compared to C18 phases, these columns show less retention due to the lower hydrophobicity.<ul><li>Ultra pure, spherical high performance HPLC phase based on silica gel</li><li>Monomeric C8 (Octyl) modification, standard endcapping, with 10 % carbon content (~ 50 % endcapping)</li></ul><h5>Properties</h5><ul><li>Separation mechanism: Hydrophobic interaction(lower compared to C18 phases)</li></ul><h5>Key features</h5><ul><li>Classical C8 phase, standard 50 % endcapping and 10 % carbon load, outstanding mechanical and chemical stability, suited for analytical as well as semi preparative and preparative applications.</li></ul><h5>Recommended application areas</h5><ul><li>Similar selectivity to C18 phase but less retention due to the lower hydrophobicity; useful for determination of:<ul><li>Water soluble vitamins</li><li>Steroids</li><li>Catecholamines</li><li>Sedatives</li></ul></li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_C8_rp_non_endcapped_3f7727d3fd.webp" alt="KNAUER: C8 RP Non-endcapped" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_C8_rp_non_endcapped_3f7727d3fd.webp 148w," sizes="100vw" width="304" height="321">Hydrophilic C8A phase offers an alternative, more polar selectivity. It is suited for highly polar reversed phase applications with up to 100 % aqueous mobile phases.&nbsp;<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_C8_A_e1f371165e.webp" alt="KNAUER: C8A" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_C8_A_e1f371165e.webp 198w," sizes="100vw" width="473" height="373"><blockquote>Tip: Caution! Even for short term storage all buffer solutions have to be rinsed from the column to prevent crystallization effects.</blockquote>Stationary phases Eurospher II 100 C8 and C8A are provided in these column types: analytical, semi-preparative and preparative.Eurospher II 100 C8 and C8A Analytical Columns are available with these parameters:<ul><li>Column length (mm): 50, 100, 150, 250</li><li>Column ID (mm): 2, 3, 4, 4.6</li><li>Particle size (µm): 2, 3, 5</li></ul>Eurospher II 100 C8 and C8A Semi-Preparative Standard Columns are available with these parameters:<ul><li>Column length (mm): 30, 50, 125, 150, 250</li><li>Column ID (mm): 8, 16</li><li>Particle size (µm): 5, 10</li></ul><h3>KNAUER (U)HPLC Columns</h3>Widest range of HPLC and UHPLC columns for all separation modes and applications.<ul><li>Safe Investment: Robust and reliable columns for attractive price&nbsp;</li><li>Separation Mode: Reversed Phase, HILIC, Normale</li><li>Simplicity: Easy purchase via our online store with fast delivery</li><li>Application: All-rounder for research or highly specialised for high-throughput analysis? We have the best column for your requirements.</li><li>Flexibility: Wide selection of column and particle sizes, for (U)HPLC applications up to 1000 bar</li></ul>KNAUER offers the perfect column for any small molecule separation. No matter which separation mode, molecule and the mobile phase, we offer a suitable (U)HPLC stationary phase. Choose from a wide range of modifications, particle sizes and column dimensions to suit your application. To elongate the lifetime of your column, you can choose to use a suitable precolumn.<figure class="image"><img style="aspect-ratio:787/674;" src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_KNAUER_U_HPLC_C8_and_C8_A_Columns_083c60f401.webp" alt="KNAUER: KNAUER (U)HPLC Columns" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_KNAUER_U_HPLC_C8_and_C8_A_Columns_083c60f401.webp 182w," sizes="100vw" width="787" height="674"></figure>

KNAUER Eurospher II 100 C18 (U)HPLC Columns (USP L1)

Stationary phase Eurospher II 100 C18 (U)HPLC is the most often used stationary phase in reversed phase mode

Classical Reversed Phase columns for HPLC and UHPLC (USP L1)Most often used stationary phase in reversed phase mode. Silica gel based columns with C18 modification are available with or without endcapping. Classically endcapped phases are slightly more hydrophobic and unpolar than the not endcapped phases.<h5>Properties</h5><ul><li>Separation mechanism: Hydrophobic interaction</li><li>Ultra pure, spherical high performance HPLC phase based on silica gel</li><li>Unpolar, monomeric C18 (Octadecyl) modification, endcapped, with 16 % carbon content (~ 50 % endcapping).</li></ul><h5>Key features</h5><ul><li>High-class HPLC phase perfectly suited to take on routine analyses as well as the most ambitious chromatography tasks, classical C18 phase with ca. 50 % endcapping and resulting 16 % carbon content, outstanding mechanical and chemical stability.</li></ul><h5>Recommended application areas</h5><ul><li>acidic, basic and neutral analytes in reversed phase mode, for example sulphonamides</li><li>anabolic steroids</li><li>anti-psychotics</li><li>beta blocker</li><li>sudan dyes</li><li>phenols and preservatives</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_C18_non_endcapped_6e4fce9989.webp" alt="KNAUER: C18 Non-endcapped" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_C18_non_endcapped_6e4fce9989.webp 245w," sizes="100vw" width="682" height="420"><blockquote>Tip: Caution! Never use classical C18 phases with 100 % aqueous mobile phase. The hydrophobic C18 chains will collapse</blockquote>Stationary phase Eurospher II 100 C18 is provided in these column types: analytical, semi-preparative and preparative.Eurospher II 100 C18 Analytical Columns are available with these parameters:<ul><li>Column length (mm): 50, 100, 150, 250</li><li>Column ID (mm): 2, 3, 4, 4.6</li><li>Particle size (µm): 2, 3, 5</li></ul>Eurospher II 100 C18 Semi-Preparative Standard Columns are available with these parameters:<ul><li>Column length (mm): 30, 50, 125, 150, 250</li><li>Column ID (mm): 8, 16</li><li>Particle size (µm): 5, 10</li></ul><h3>KNAUER (U)HPLC Columns</h3>Widest range of HPLC and UHPLC columns for all separation modes and applications.<ul><li>Safe Investment: Robust and reliable columns for attractive price&nbsp;</li><li>Separation Mode: Reversed Phase, HILIC, Normale</li><li>Simplicity: Easy purchase via our online store with fast delivery</li><li>Application: All-rounder for research or highly specialised for high-throughput analysis? We have the best column for your requirements.</li><li>Flexibility: Wide selection of column and particle sizes, for (U)HPLC applications up to 1000 bar</li></ul>KNAUER offers the perfect column for any small molecule separation. No matter which separation mode, molecule and the mobile phase, we offer a suitable (U)HPLC stationary phase. Choose from a wide range of modifications, particle sizes and column dimensions to suit your application. To elongate the lifetime of your column, you can choose to use a suitable precolumn.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_KNAUER_U_HPLC_C8_and_C8_A_Columns_083c60f401.webp" alt="KNAUER: KNAUER (U)HPLC Columns" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_KNAUER_U_HPLC_C8_and_C8_A_Columns_083c60f401.webp 182w," sizes="100vw" width="787" height="674">

KNAUER Eurospher II Chiral NR Columns for NP & RP

Eurospher II Chiral NR is an immobilized brush-type phase with very broad generality and orhogonal selectivity to Eurospher II Chiral AM and OM.

Eurospher II Chiral NR is an immobilized brush-type phase with very broad generality and orhogonal selectivity to Eurospher II Chiral AM and OM. In many cases it is much more stable compared to Eurospher II Chiral AM or OM. The Chiral-NR selector is covalently bound, so that you can use all HPLC-eluents.Due to its high loadability it is perfectly suited for preparative separations. Both phases can be used in RP and NP mode. Eurospher II Chiral-NR-R shows reversed elution order compared to Eurospher II Chiral-NR caused by the modification with the opposite enantiomeric form of the chiral selector.<h5>Properties</h5><ul><li>Silica gel: ultra pure, &gt; 99.99 %</li><li>Metal content: &lt; 10 ppm</li><li>Particle size:&nbsp;<ul><li>Eurospher II Chiral NR: 3 μm, 5 μm, 8 µm, 12 µm</li><li>Eurospher II Chiral NR-R: 8 µm, 12 µm</li></ul></li><li>Particle form: spherical</li><li>Pore size of base material: 1000 Å</li></ul><h5>Recommended application areas</h5><ul><li>Eurospher II Chiral NR columns are able to separate analytes with an oxygen at or near the chiral center and additionally an aromatic ring.</li></ul><blockquote>Stationary phase Eurospher II Chiral NR (NR-R) is provided in these column types: analytical, semi-preparative and preparative.</blockquote>Eurospher II Chiral NR and NR-R Analytical Columns are available with these parameters:<ul><li>Column length (mm): 50, 100, 150, 250</li><li>Column ID (mm): 3, 4, 4.6</li><li>Particle size (µm): 3, 5, 8, 12</li></ul>Eurospher II Chiral NR and NR-R Semi-Preparative Standard Columns are available with these parameters:<ul><li>Column length (mm): 150, 250</li><li>Column ID (mm): 8, 10</li><li>Particle size (µm): 8, 12</li></ul><h3>KNAUER Chiral HPLC Columns</h3>For analytical, preparative and SMB chiral separations<ul><li>Column Brand<ul><li>Eurospher II</li></ul></li><li>Reversed Phase Modifications<ul><li>Chiral NR-R</li><li>Chiral AM-R</li><li>Chiral OM-R</li></ul></li><li>Normal Phase Modifications<ul><li>Chiral NR</li><li>Chiral AM</li><li>Chiral OM</li></ul></li><li>Flexibility: Wide selection of column and particle sizes, for preparative and analytical applications</li><li>Expandable: Upscaling even for continuous SMB</li><li>Application Service: We offer a customized screening service for your analytes. You will receive an optimal column recommendation including the method parameters.</li></ul><h4>Eurospher II Chiral</h4>Based on ultra-high purity silica, the Eurospher II chiral column materials are characterized by high enantioselectivity and loadability.&nbsp;Available in a wide range of dimensions for analytical, preparative and SMB (simulated moving bed) applications, Eurospher II Chiral columns are the perfect choice for even the most challenging enantioseparation tasks&nbsp;Since chiral separations are not very well predictable, KNAUER offers a chiral screening service for your samples (Article number: AL0220).<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurospher_II_chiral_48c53afebe.jpg" alt="KNAUER: Eurospher II chiral" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurospher_II_chiral_48c53afebe.jpg 245w," sizes="100vw" width="1369" height="633"><blockquote>Tip: Some of the most popular eluents for HPLC (such as acetone, chloroform, DMF, DMSO, MEK, toluene, dioxane, ethyl acetate, methylene chloride, pyridine and THF) which may be remaining in your HPLC system, can destroy Eurospher II Chiral AM and OM phases even in small concentrations! It is highly recommended that the HPLC system is flushed with appropriate eluents before the installation of the chiral column.</blockquote>

KNAUER Eurokat H Ion Exclusion/Ligand Exchange Columns (USP L17)

The Eurokat H ionic form is especially designed for the analysis of organic acids and even complex mixtures of acids, sugars and alcohols as well as sugar alcohols.

Organic acids and alcoholsThe Eurokat H ionic form is especially designed for the analysis of organic acids and even complex mixtures of acids, sugars and alcohols as well as sugar alcohols. It is a cation exchange material with 8 % cross linkage of the styrenedivinylbenzene copolymer. Best results are acieved with aqueous eluents and small amounts of anorganic acids, recommended eluent 0.005 M sulfuric acid. The usage of up to 10 % organic content in the mobile phase is possible.<h5>Properties</h5><ul><li>Sulfonated cross-linked styrenedivinylbenzene copolymer phase for the determination of organic acids, carbohydrates and alcohols</li><li>H-form, 8 % cross linkage</li><li>Cation exchanger, extremly long lasting lifetime when correctly handled, best results with aqueous eluents and small amounts of anorganic acids, recommended eluent 0,01 N sulfuric acid, usage of up to 10 % organic content in the mobile phase is possible</li></ul><h5>Technical Data</h5><ul><li>Sulfonated cross-linked styrenedivinylbenzene copolymer with 8 % cross linkage in the ionic form H, available in 10 μm particle size, pressure stable up to maximum 100 bar</li></ul><h5>Recommended application areas</h5><ul><li>Eurokat H is especially designed for the analysis of organic acids and even complex mixtures of acids, sugars and alcohols as well as sugar alcohols. Due to a differing separation process we recommend the use of these type of columns only in 8 mm ID or 4 mm ID.</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurokat_H_Chromatogram_e2c6665a1f.webp" alt="KNAUER: Eurokat H Chromatogram" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurokat_H_Chromatogram_e2c6665a1f.webp 245w," sizes="100vw" width="690" height="281"><blockquote>Tip: Eurokat columns are characterized by an extremely long lifetime if handled properly. Especially pressure shocks and organic solvent contents of more than 10 % in the mobile phase should be avoided absolutely.</blockquote><h3>KNAUER Ion Exclusion and Ligand Exchange Columns</h3>Separation of organic acids, carbohydrates, alcohols on sulfonated cross-linked styrenedivinylbenzene copolymer<ul><li>Modifications<ul><li>Eurokat H</li><li>Eurokat Ca</li><li>Eurokat Pb</li><li>Eurokat Na</li></ul></li><li>High Temperature Methods: Up to 90 °C</li><li>Method Development: Optional up to 10 % organic solvent</li><li>Chemically stable: pH 1–12</li><li>Sustainability: Aqueous eluents protect the environment and are cost-effectiv</li><li>User Friendly: Simple and robust methods for daily analysis. Versatile in its use.</li><li>Simplicity: Easy purchase via our online store with fast delivery.&nbsp;</li></ul><h4>Characteristics&nbsp;</h4>Eurokat high performance polymer phases were especially developed for the separation of organic acids, carbohydrates, alcohols and even complex mixtures of these compounds. Eurokat is a sulfonated cross-linked styrenedivinylbenzene copolymer available in several ionic forms (H, Ca and Pb). This particular cation exchanger is characterized by an outstanding density of functional groups, making it the ideal choice for your ion exclusion, size exclusion and ligand exchange chromatography.<h4>Choice of chromatographic conditions&nbsp;</h4>The Eurokat stationary phase is designed to be applicable to a wide range of diverse chromatographic conditions. All Eurokat columns can be used at temperatures up to 90 °C with no organic solvents. The best separation of sugars can be achieved using between 60 to 90 °C. To extend separation performance, it is possible to connect up to three columns of Eurokat in series. Eurokat columns require no organic solvents and thus are environmentally friendly.&nbsp;<h4>Stability&nbsp;</h4>Eurokat polymer columns are extremely stable over the whole pH range. This is one striking advantage compared with silica-based phases which have a limited lifetime at pH extremes, especially in the higher pH range. Most importantly, Eurokat phases show extraordinary column lifetime stability and are not affected by aqueous solvents.&nbsp;<h4>Application areas&nbsp;</h4><ul><li>Carbohydrates and organic acids in softdrinks and fruit juices&nbsp;</li><li>Sugar substitutes</li><li>Food preservatives</li><li>Dairy products</li><li>Urine analytic (Uric acid, Hippuric acid)</li><li>Monitoring of fermentation processes</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Principle_of_ligand_exchange_mechanism_a5b7c21c43.jpg" alt="KNAUER: Eurokat - Principle of ligand exchange mechanism" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Principle_of_ligand_exchange_mechanism_a5b7c21c43.jpg 245w," sizes="100vw" width="1382" height="570">

KNAUER Eurokat Pb & Ca Ion Exclusion/Ligand Exchange Columns (USP L34 / USP L19)

The ionic forms Ca and Pb are best suited for the analysis of smaller carbohydrates like mono- and disaccharides and sugars up to a degree of polymerization (DP) of 4. 

Analysis of mono- and disaccharidesThe ionic forms Ca and Pb are best suited for the analysis of smaller carbohydrates like mono- and disaccharides and sugars up to a degree of polymerization (DP) of 4. It is a cation exchange material with 6 % cross linkage of the styrenedivinylbenzene copolymer. Best results are achieved with aqueous eluents, recommended eluent is pure deionized water. The usage of up to 10 % organic content in the mobile phase is possible.<h5>Properties</h5><ul><li>Polymer phase for the determination of mono- and disaccharides</li><li>Pb (USP L34) form, 6 % cross linkage</li><li>Cation exchanger, extremely long lasting lifetime when correctly handled, best results with aqueous eluents, recommended eluent is pure deionized water, usage of up to 10 % organic content in the mobile phase is possible</li></ul><h5>Technical Data</h5><ul><li>Sulfonated cross-linked styrenedivinylbenzene copolymer with 6 % cross linkage in the ionic form Pb, available in 10μm particle size, pressure stable up to maximum 100 bar</li></ul><h5>Recommended application areas</h5><ul><li>Especially designed for the analysis of small carbohydrates up to DP 4</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurokat_Pb_Ca_Chromatogram_2054f70e49.webp" alt="KNAUER: Eurokat Pb &amp; Ca Chromatogram" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurokat_Pb_Ca_Chromatogram_2054f70e49.webp 245w," sizes="100vw" width="690" height="271"><blockquote>Tip: Eurokat columns are used at high temperatures. During equilibration it is very important to have an eye on the backpressure and to start with very low flow rates and increase them only slowly and stepwise after the column has adapted to the temperature.</blockquote><h3>KNAUER Ion Exclusion and Ligand Exchange Columns</h3>Separation of organic acids, carbohydrates, alcohols on sulfonated cross-linked styrenedivinylbenzene copolymer<ul><li>Modifications<ul><li>Eurokat H</li><li>Eurokat Ca</li><li>Eurokat Pb</li><li>Eurokat Na</li></ul></li><li>High Temperature Methods: Up to 90 °C</li><li>Method Development: Optional up to 10 % organic solvent</li><li>Chemically stable: pH 1–12</li><li>Sustainability: Aqueous eluents protect the environment and are cost-effectiv</li><li>User Friendly: Simple and robust methods for daily analysis. Versatile in its use.</li><li>Simplicity: Easy purchase via our online store with fast delivery.&nbsp;</li></ul><h4>Characteristics&nbsp;</h4>Eurokat high performance polymer phases were especially developed for the separation of organic acids, carbohydrates, alcohols and even complex mixtures of these compounds. Eurokat is a sulfonated cross-linked styrenedivinylbenzene copolymer available in several ionic forms (H, Ca and Pb). This particular cation exchanger is characterized by an outstanding density of functional groups, making it the ideal choice for your ion exclusion, size exclusion and ligand exchange chromatography.<h4>Choice of chromatographic conditions&nbsp;</h4>The Eurokat stationary phase is designed to be applicable to a wide range of diverse chromatographic conditions. All Eurokat columns can be used at temperatures up to 90 °C with no organic solvents. The best separation of sugars can be achieved using between 60 to 90 °C. To extend separation performance, it is possible to connect up to three columns of Eurokat in series. Eurokat columns require no organic solvents and thus are environmentally friendly.&nbsp;<h4>Stability&nbsp;</h4>Eurokat polymer columns are extremely stable over the whole pH range. This is one striking advantage compared with silica-based phases which have a limited lifetime at pH extremes, especially in the higher pH range. Most importantly, Eurokat phases show extraordinary column lifetime stability and are not affected by aqueous solvents.&nbsp;<h4>Application areas&nbsp;</h4><ul><li>Carbohydrates and organic acids in softdrinks and fruit juices&nbsp;</li><li>Sugar substitutes</li><li>Food preservatives</li><li>Dairy products</li><li>Urine analytic (Uric acid, Hippuric acid)</li><li>Monitoring of fermentation processes</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Principle_of_ligand_exchange_mechanism_a5b7c21c43.jpg" alt="KNAUER: Eurokat - Principle of ligand exchange mechanism" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Principle_of_ligand_exchange_mechanism_a5b7c21c43.jpg 245w," sizes="100vw" width="1382" height="570">

KNAUER Eurokat Na Ion Exclusion/Ligand Exchange Columns

The ionic form Na is best suited for the analysis of sugars oligomers up to a degree of polymerization (DP) of 8. 

Analysis of sugar oligomersThe ionic form Na is best suited for the analysis of sugars oligomers up to a degree of polymerization (DP) of 8. It is a cation exchange material with 6 % cross linkage of the styrenedivinylbenzene copolymer. Best results are achieved with aqueous eluents, recommended eluent is pure deionized water. The usage of up to 10 % organic content in the mobile phase is possible.&nbsp;<h5>Properties</h5><ul><li>Polymer phase for the determination of sugar oligomers</li><li>Na form, 6 % cross linkage</li><li>Cation exchanger, extremly long lasting lifetime when correctly handled, best results with aqueous eluents, recommended eluent is pure deionized water, usage of up to 10 % organic content in the mobile phase is possible</li></ul><h5>Technical Data</h5><ul><li>Sulfonated cross-linked styrenedivinylbenzene copolymer with 6 % cross linkage in the ionic form Na, available in 10 μm particle size, pressure stable up to maximum 100 bar</li></ul><h5>Recommended application areas</h5><ul><li>Especially designed for the analysis of sugar oligomers, separates carbohydrates up to DP 8</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurokat_Na_Chromatogram_7d3d81fa52.webp" alt="KNAUER: Eurokat Na Chromatogram" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurokat_Na_Chromatogram_7d3d81fa52.webp 188w," sizes="100vw" width="686" height="568"><blockquote>Tip: Eurokat columns are typically used with 100 % aqueous eluents. For storage, please avoid microbial growth by flushing the Eurokat column with 0.45 µm filtered ultrapure water and storing it at 4 °C.</blockquote><h3>KNAUER Ion Exclusion and Ligand Exchange Columns</h3>Separation of organic acids, carbohydrates, alcohols on sulfonated cross-linked styrenedivinylbenzene copolymer<ul><li>Modifications<ul><li>Eurokat H</li><li>Eurokat Ca</li><li>Eurokat Pb</li><li>Eurokat Na</li></ul></li><li>High Temperature Methods: Up to 90 °C</li><li>Method Development: Optional up to 10 % organic solvent</li><li>Chemically stable: pH 1–12</li><li>Sustainability: Aqueous eluents protect the environment and are cost-effectiv</li><li>User Friendly: Simple and robust methods for daily analysis. Versatile in its use.</li><li>Simplicity: Easy purchase via our online store with fast delivery.&nbsp;</li></ul><h4>Characteristics&nbsp;</h4>Eurokat high performance polymer phases were especially developed for the separation of organic acids, carbohydrates, alcohols and even complex mixtures of these compounds. Eurokat is a sulfonated cross-linked styrenedivinylbenzene copolymer available in several ionic forms (H, Ca and Pb). This particular cation exchanger is characterized by an outstanding density of functional groups, making it the ideal choice for your ion exclusion, size exclusion and ligand exchange chromatography.<h4>Choice of chromatographic conditions&nbsp;</h4>The Eurokat stationary phase is designed to be applicable to a wide range of diverse chromatographic conditions. All Eurokat columns can be used at temperatures up to 90 °C with no organic solvents. The best separation of sugars can be achieved using between 60 to 90 °C. To extend separation performance, it is possible to connect up to three columns of Eurokat in series. Eurokat columns require no organic solvents and thus are environmentally friendly.&nbsp;<h4>Stability&nbsp;</h4>Eurokat polymer columns are extremely stable over the whole pH range. This is one striking advantage compared with silica-based phases which have a limited lifetime at pH extremes, especially in the higher pH range. Most importantly, Eurokat phases show extraordinary column lifetime stability and are not affected by aqueous solvents.&nbsp;<h4>Application areas&nbsp;</h4><ul><li>Carbohydrates and organic acids in softdrinks and fruit juices&nbsp;</li><li>Sugar substitutes</li><li>Food preservatives</li><li>Dairy products</li><li>Urine analytic (Uric acid, Hippuric acid)</li><li>Monitoring of fermentation processes</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Principle_of_ligand_exchange_mechanism_a5b7c21c43.jpg" alt="KNAUER: Eurokat - Principle of ligand exchange mechanism" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Principle_of_ligand_exchange_mechanism_a5b7c21c43.jpg 245w," sizes="100vw" width="1382" height="570">

KNAUER Eurosil Bioselect 300 C4 HPLC Columns (USP L26)

Eurosil Bioselect C4 has been specifically developed for the determination and purification of peptides, proteins, and oligonucleotides up to a molecular weight of approximately 100 kDa. 

Analytical wide pore phase for the determination of biomolecules bigger than 20 kDaEurosil Bioselect C4 has been specifically developed for the determination and purification of peptides, proteins, and oligonucleotides up to a molecular weight of approximately 100 kDa. The optimized manufacturing process guarantees excellent batch–to-batch reproducibility. The Eurosil Bioselect sorbent is the first choice for Biochromatography with silica material.<h5>Properties</h5><ul><li>Ultra pure, spherical wide pore HPLC phase based on wide pore silica gel</li><li>Unpolar, monomeric C4 modification, endcapped</li><li>2 % carbon content (conventional endcapping)</li><li>Separation mechanism: hydrophobic and hydrophilic interaction</li></ul><figure class="image"><img style="aspect-ratio:200/400;" src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_C4_3f3adfbdb4.webp" alt="KNAUER: C4" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_C4_3f3adfbdb4.webp 78w," sizes="100vw" width="200" height="400"></figure><h5>Recommended application areas</h5><ul><li>Hydrophilic biomolecules and especially peptides larger than 10 000- 20 000 Da</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurosil_Bioselect_Phases_98acc32d0e.jpg" alt="KNAUER: Eurosil Bioselect - Phases and recommended sizes of molecules" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurosil_Bioselect_Phases_98acc32d0e.jpg 245w," sizes="100vw" width="1385" height="778"><h3>KNAUER Wide pore HPLC columns</h3>For enhanced resolution, capacity and recovery of proteins and other biomolecules<ul><li>Material: Silica or polymer particles</li><li>Separation Ranges: 2–100 kDa</li><li>Column Brands: Eurosil Bioselect or AppliChrom®</li><li>Particle sizes: 3–10 µm</li><li>Pore Sizes: 300 or 100–1000 Å</li><li>Specific surface: 90 ± 5 m2/g</li><li>Pore volume: 0.8 ml/g</li><li>Density: 450 g/l</li><li>Applications: Peptides exceeding approximately 50 amino acids and oligonucleotides greater than 25 residues</li><li>Customize: Bioanalysis requires a lot of flexibility in the pore size, the pH range, the temperatures and the solvents used. To achieve this, we cross phase limits.</li></ul><h4>Characteristics&nbsp;</h4><ul><li>Eurosil Bioselect columns are available in 4 modifications, useful for a wide range of separation tasks involving large molecules up to 100 000 Da.</li><li>Strict manufacturing procedures ensure a very narrow pore size distribution.</li><li>Interfering anions or heavy metal ions on the silica surface are not present in Eurosil Bioselect columns because only ultra pure silica gel and high quality chemical modifications are employed.</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurosil_Bioselect_85cfc2d201.jpg" alt="KNAUER: Eurosil Bioselect" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurosil_Bioselect_85cfc2d201.jpg 222w," sizes="100vw" width="1114" height="782"><h4>Separation mechanism of Eurosil Bioselect</h4>To separate larger molecules, they need to freely access the interior of the pores of the packing material. Therefore, the analytes’ diameter must be smaller than the average pore diameter.&nbsp;For higher molecular weight solutes, the use of lower pore size materials (60-120 Å) as typically used for the analysis of small molecules may result restricted diffusion in the material´s pores and therewith reduced column efficiency.&nbsp;<h4>Modifications</h4>The recommended modification of Eurosil Bioselect depends on the molecular weight of the analytes.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurosil_Bioselect_chemical_modifications_1fd5d87f7b.jpg" alt="KNAUER: Eurosil Bioselect - chemical modifications" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurosil_Bioselect_chemical_modifications_1fd5d87f7b.jpg 245w," sizes="100vw" width="955" height="505"> &nbsp;

KNAUER Eurosil Bioselect 300 C8 HPLC Columns (USP L7)

Eurosil Bioselect C8 has been specifically developed for the determination and purification of peptides, proteins, and oligonucleotides up to a molecular weight of approximately 20 kDa.

Analytical wide pore phase for the determination of biomolecules bigger than 5000 DaEurosil Bioselect C8 has been specifically developed for the determination and purification of peptides, proteins, and oligonucleotides up to a molecular weight of approximately 20 kDa.<h5>Properties</h5><ul><li>Ultra pure, spherical wide pore HPLC phase based on wide pore silica gel</li><li>Unpolar, monomeric C8 modification, endcapped</li><li>4.5 % carbon content (conventional endcapping)</li><li>Separation mechanism: hydrophobic interaction</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_C8_hydrosphob_6986c292b4.webp" alt="KNAUER: C8" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_C8_hydrosphob_6986c292b4.webp 144w," sizes="100vw" width="381" height="413"><h5>Recommended application areas</h5><ul><li>Hydrophilic biomolecules, peptides, peptide mapping after enzymatic digestion</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurosil_Bioselect_Phases_98acc32d0e.jpg" alt="KNAUER: Eurosil Bioselect - Phases and recommended sizes of molecules" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurosil_Bioselect_Phases_98acc32d0e.jpg 245w," sizes="100vw" width="1385" height="778"><h3>KNAUER Wide pore HPLC columns</h3>For enhanced resolution, capacity and recovery of proteins and other biomolecules<ul><li>Material: Silica or polymer particles</li><li>Separation Ranges: 2–100 kDa</li><li>Column Brands: Eurosil Bioselect or AppliChrom®</li><li>Particle sizes: 3–10 µm</li><li>Pore Sizes: 300 or 100–1000 Å</li><li>Specific surface: 90 ± 5 m2/g</li><li>Pore volume: 0.8 ml/g</li><li>Density: 450 g/l</li><li>Applications: Peptides exceeding approximately 50 amino acids and oligonucleotides greater than 25 residues</li><li>Customize: Bioanalysis requires a lot of flexibility in the pore size, the pH range, the temperatures and the solvents used. To achieve this, we cross phase limits.</li></ul><h4>Characteristics&nbsp;</h4><ul><li>Eurosil Bioselect columns are available in 4 modifications, useful for a wide range of separation tasks involving large molecules up to 100 000 Da.</li><li>Strict manufacturing procedures ensure a very narrow pore size distribution.</li><li>Interfering anions or heavy metal ions on the silica surface are not present in Eurosil Bioselect columns because only ultra pure silica gel and high quality chemical modifications are employed.</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurosil_Bioselect_85cfc2d201.jpg" alt="KNAUER: Eurosil Bioselect" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurosil_Bioselect_85cfc2d201.jpg 222w," sizes="100vw" width="1114" height="782"><h4>Separation mechanism of Eurosil Bioselect</h4>To separate larger molecules, they need to freely access the interior of the pores of the packing material. Therefore, the analytes’ diameter must be smaller than the average pore diameter.&nbsp;For higher molecular weight solutes, the use of lower pore size materials (60-120 Å) as typically used for the analysis of small molecules may result restricted diffusion in the material´s pores and therewith reduced column efficiency.&nbsp;<h4>Modifications</h4>The recommended modification of Eurosil Bioselect depends on the molecular weight of the analytes.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurosil_Bioselect_chemical_modifications_1fd5d87f7b.jpg" alt="KNAUER: Eurosil Bioselect - chemical modifications" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurosil_Bioselect_chemical_modifications_1fd5d87f7b.jpg 245w," sizes="100vw" width="955" height="505"> &nbsp;

KNAUER Eurosil Bioselect 300 C18 HPLC Columns (USP L1)

Eurosil Bioselect C18 has been specifically developed for the determination and purification of peptides, proteins, and oligonucleotides up to a molecular weigth of approximately 5 kDa.

Analytical wide pore phase for the determination of biomolecules bigger than 2000 Da​Eurosil Bioselect C18 has been specifically developed for the determination and purification of peptides, proteins, and oligonucleotides up to a molecular weigth of approximately 5 kDa.<h5>Properties</h5><ul><li>Ultra pure, spherical wide pore HPLC phase based on silica gel</li><li>Unpolar, monomeric C18 (Octadecyl) modification, endcapped</li><li>7.5 % carbon content (conventional endcapping)</li><li>Separation mechanism: hydrophobic interaction</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_C18_Endcapped_standard_edd2523aca.webp" alt="KNAUER: C18 Endcapped standard" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_C18_Endcapped_standard_edd2523aca.webp 234w," sizes="100vw" width="688" height="458"><h5>Recommended application areas</h5><ul><li>Hydrophilic biomolecules, peptides, peptide mapping after enzymatic digestion</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurosil_Bioselect_Phases_98acc32d0e.jpg" alt="KNAUER: Eurosil Bioselect - Phases and recommended sizes of molecules" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurosil_Bioselect_Phases_98acc32d0e.jpg 245w," sizes="100vw" width="1385" height="778"><blockquote>Tip: Caused by the larger pore size of 300 Å, Eurosil Bioselect phases are not as mechanical stable as classical silica gel phases with up to 150 Å and should not be used above 200 bar pressure.</blockquote><h3>KNAUER Wide pore HPLC columns</h3>For enhanced resolution, capacity and recovery of proteins and other biomolecules<ul><li>Material: Silica or polymer particles</li><li>Separation Ranges: 2–100 kDa</li><li>Column Brands: Eurosil Bioselect or AppliChrom®</li><li>Particle sizes: 3–10 µm</li><li>Pore Sizes: 300 or 100–1000 Å</li><li>Specific surface: 90 ± 5 m2/g</li><li>Pore volume: 0.8 ml/g</li><li>Density: 450 g/l</li><li>Applications: Peptides exceeding approximately 50 amino acids and oligonucleotides greater than 25 residues</li><li>Customize: Bioanalysis requires a lot of flexibility in the pore size, the pH range, the temperatures and the solvents used. To achieve this, we cross phase limits.</li></ul><h4>Characteristics&nbsp;</h4><ul><li>Eurosil Bioselect columns are available in 4 modifications, useful for a wide range of separation tasks involving large molecules up to 100 000 Da.</li><li>Strict manufacturing procedures ensure a very narrow pore size distribution.</li><li>Interfering anions or heavy metal ions on the silica surface are not present in Eurosil Bioselect columns because only ultra pure silica gel and high quality chemical modifications are employed.</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurosil_Bioselect_85cfc2d201.jpg" alt="KNAUER: Eurosil Bioselect" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurosil_Bioselect_85cfc2d201.jpg 222w," sizes="100vw" width="1114" height="782"><h4>Separation mechanism of Eurosil Bioselect</h4>To separate larger molecules, they need to freely access the interior of the pores of the packing material. Therefore, the analytes’ diameter must be smaller than the average pore diameter.&nbsp;For higher molecular weight solutes, the use of lower pore size materials (60-120 Å) as typically used for the analysis of small molecules may result restricted diffusion in the material´s pores and therewith reduced column efficiency.&nbsp;<h4>Modifications</h4>The recommended modification of Eurosil Bioselect depends on the molecular weight of the analytes.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurosil_Bioselect_chemical_modifications_1fd5d87f7b.jpg" alt="KNAUER: Eurosil Bioselect - chemical modifications" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurosil_Bioselect_chemical_modifications_1fd5d87f7b.jpg 245w," sizes="100vw" width="955" height="505"> &nbsp;

KNAUER Eurosil Bioselect 300 C18A HPLC Columns (USP L1)

Eurosil Bioselect C18A has been specifically developed for the determination and purification of peptides, proteins, and oligonucleotides up to a molecular weigth of approximately 5 kDa.

Analytical wide pore phase for the determination of biomolecules up to 5000 Da​Eurosil Bioselect C18A has been specifically developed for the determination and purification of peptides, proteins, and oligonucleotides up to a molecular weigth of approximately 5 kDa.<h5>Properties</h5><ul><li>Ultra pure, spherical wide pore HPLC phase based on silica gel</li><li>Unpolar, monomeric C18 (Octadecyl) modification, endcapped</li><li>7 % carbon content (hydrophilic endcapping)</li><li>Separation mechanism: hydrophobic interaction</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_C18_A_6f4b0c3063.webp" alt="KNAUER: C18A" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_C18_A_6f4b0c3063.webp 245w," sizes="100vw" width="690" height="428"><h5>Recommended application areas</h5><ul><li>Hydrophilic and polar biomolecules, peptides, very polar biomolecules separated with 100 % aqueous eluents</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurosil_Bioselect_Phases_98acc32d0e.jpg" alt="KNAUER: Eurosil Bioselect - Phases and recommended sizes of molecules" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurosil_Bioselect_Phases_98acc32d0e.jpg 245w," sizes="100vw" width="1385" height="778"><h3>KNAUER Wide pore HPLC columns</h3>For enhanced resolution, capacity and recovery of proteins and other biomolecules<ul><li>Material: Silica or polymer particles</li><li>Separation Ranges: 2–100 kDa</li><li>Column Brands: Eurosil Bioselect or AppliChrom®</li><li>Particle sizes: 3–10 µm</li><li>Pore Sizes: 300 or 100–1000 Å</li><li>Specific surface: 90 ± 5 m2/g</li><li>Pore volume: 0.8 ml/g</li><li>Density: 450 g/l</li><li>Applications: Peptides exceeding approximately 50 amino acids and oligonucleotides greater than 25 residues</li><li>Customize: Bioanalysis requires a lot of flexibility in the pore size, the pH range, the temperatures and the solvents used. To achieve this, we cross phase limits.</li></ul><h4>Characteristics&nbsp;</h4><ul><li>Eurosil Bioselect columns are available in 4 modifications, useful for a wide range of separation tasks involving large molecules up to 100 000 Da.</li><li>Strict manufacturing procedures ensure a very narrow pore size distribution.</li><li>Interfering anions or heavy metal ions on the silica surface are not present in Eurosil Bioselect columns because only ultra pure silica gel and high quality chemical modifications are employed.</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurosil_Bioselect_85cfc2d201.jpg" alt="KNAUER: Eurosil Bioselect" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurosil_Bioselect_85cfc2d201.jpg 222w," sizes="100vw" width="1114" height="782"><h4>Separation mechanism of Eurosil Bioselect</h4>To separate larger molecules, they need to freely access the interior of the pores of the packing material. Therefore, the analytes’ diameter must be smaller than the average pore diameter.&nbsp;For higher molecular weight solutes, the use of lower pore size materials (60-120 Å) as typically used for the analysis of small molecules may result restricted diffusion in the material´s pores and therewith reduced column efficiency.&nbsp;<h4>Modifications</h4>The recommended modification of Eurosil Bioselect depends on the molecular weight of the analytes.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Eurosil_Bioselect_chemical_modifications_1fd5d87f7b.jpg" alt="KNAUER: Eurosil Bioselect - chemical modifications" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Eurosil_Bioselect_chemical_modifications_1fd5d87f7b.jpg 245w," sizes="100vw" width="955" height="505"> &nbsp;

Products from category Analytical HPLC columns - page 11

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