In German, there is a well-known saying: “Der April macht, was er will!” — loosely translated as “April does whatever it wants.” While this usually refers to unpredictable weather, it can sometimes describe other situations just as well.As an analytical application specialist at KNAUER, I was genuinely excited when, at the end of 2023, my colleague and product manager Mareike Myrach and I were assigned the project of the <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/1454">Liquid Handler LH 8.1</a>. At that time, we had no prior hands-on experience with the system, but we quickly got up to speed — largely because learning by doing turned out to be surprisingly intuitive.Following an intensive phase of testing, method development, and optimization, the Liquid Handler LH 8.1 was officially introduced by KNAUER in April 2025. Returning to the April proverb — this time, April behaved quite differently. Rather than being unpredictable, everything came together smoothly (even if not weather-wise!). All documentation was finalized, product configurations defined, and specifications locked in. It was a very satisfying milestone.&nbsp;<h3>What makes the Liquid Handler LH 8.1 stand out?</h3>Let’s take a closer look at some of its key features.<h4>Flexible configuration tailored to your workflow</h4>The KNAUER LH 8.1 is a highly customizable XYZ autosampler designed to adapt to a wide range of laboratory requirements. It supports numerous modules and accessories, allowing users to build a system that fits their specific applications.Core components include the injection valve, the Robotic Cooler, and the fast wash station — all essential for efficient operation. Beyond these, we are continuously exploring additional enhancements.&nbsp;For example, how about seasonal upgrade kits?<ul><li>LH 8.1 Easter edition</li><li>LH 8.1 Christmas edition</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_1_Left_LH_8_1_Upgrade_Kit_7b9a711bab.jpg" alt="KNAUER: Fig. 1: Left: LH 8.1 Upgrade Kit “Easter”, right: LH 8.1 Upgrade Kit “Christmas” (limited availability — only 1 in stock!)" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_1_Left_LH_8_1_Upgrade_Kit_7b9a711bab.jpg 234w," sizes="100vw" width="1263" height="843"><h4>Flexible sample storage and high-throughput capability</h4>For laboratories focused on high-throughput analysis, the Robotic Cooler module is indispensable. Each unit can accommodate up to three sample racks, with 130 vials per rack — totaling 390 vials per module.Depending on the rail length, multiple Robotic Coolers can be installed and operated independently. On the longest rail configuration, up to three modules can be used simultaneously, increasing the total capacity of a single LH 8.1 system to as many as 1,170 vials (1.5 mL each).Naturally, the system is not limited to standard vials. It can store a variety of sample types within a temperature range of 4–40 °C.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_2_Left_Tray_with_common_samples_middle_tray_with_special_samples_right_very_very_special_samples_b1d2e3daea.jpg" alt="KNAUER: Fig. 2: Left: tray with standard samples, middle: tray with specialized samples, right: very special samples" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_2_Left_Tray_with_common_samples_middle_tray_with_special_samples_right_very_very_special_samples_b1d2e3daea.jpg 245w," sizes="100vw" width="1176" height="402"><h4>True zero sample loss</h4>Have you ever encountered the concept of “sandwich injections” in liquid chromatography? It may sound unusual at first. Replace the bread with standard HPLC solvents and the filling with your sample, separated by small air gaps — and you have a liquid “sandwich.”The LH 8.1 takes this concept even further. It allows sampling from virtually any container type. Whether it’s a standard vial or something more unconventional — like a filled chocolate egg — the system can handle it. The result? A rather creative “egg sandwich.”<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_3_Left_Exemplary_sandwich_build_up_right_aspiration_from_double_coated_chocolate_sample_container_8e9f9fa243.jpg" alt="KNAUER: Fig. 3: Left: example of sandwich configuration, right: aspiration from a chocolate-based sample container" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_3_Left_Exemplary_sandwich_build_up_right_aspiration_from_double_coated_chocolate_sample_container_8e9f9fa243.jpg 245w," sizes="100vw" width="1218" height="751"><blockquote>Please note: using such unconventional containers may significantly increase both carryover and... enjoyment.</blockquote><h4>Carryover and injection precision</h4>When evaluating HPLC injectors, injection precision is one of the most critical parameters. After optimizing the injection conditions, we achieved excellent performance.To ensure ease of use, all optimized parameters have been integrated into the software drivers. This allows users to benefit from high precision without complex programming.<h5>Injection precision (RSD):</h5><ul><li>Full loop injection: ≤ 0.10%</li><li>Sandwich injection (&gt;5 µL): ≤ 0.15%</li></ul>Another key parameter is sample carryover, evaluated using recommended washing protocols. During testing, we measured carryover using chlorhexidine as a standard compound to allow comparison with other autosamplers. Additionally, caffeine was tested due to its widespread use and accessibility in laboratories.Taking advantage of the LH 8.1’s flexibility, we also explored sampling from unconventional containers.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_4_Exemplary_sample_take_up_for_the_determination_of_carry_over_47706172c7.jpg" alt="KNAUER: Fig. 4: Left: injection of diluted caffeine sample for quantification, right: injection of concentrated sample for carryover assessment" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_4_Exemplary_sample_take_up_for_the_determination_of_carry_over_47706172c7.jpg 224w," sizes="100vw" width="1248" height="870"><h5>Measured carryover values:</h5><ul><li>Chlorhexidine: &lt; 0.005%</li><li>Caffeine: &lt; 0.002%</li></ul>Returning to the beginning of this article — you may have noticed that not only “April does whatever it wants,” but sometimes KNAUER blog authors do as well.Despite the seasonal theme, we hope you discovered a few hidden “Easter eggs” throughout the text — and didn’t take everything too seriously.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_5_KNAUER_blog_authors_72de1a0c72.jpg" alt="KNAUER: Fig. 5: KNAUER blog authors" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_5_KNAUER_blog_authors_72de1a0c72.jpg 237w," sizes="100vw" width="1150" height="757"><blockquote><ul><li>More reputable information: <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/1454">KNAUER Liquid Handler LH 8.1</a></li></ul></blockquote>

Seasonal update on liquid handling

News from LabRulezLCMS Library - Week 17, 2026

<h4>Let’s begin with a simple question: what do we actually mean by high throughput?</h4>In the laboratory, high throughput usually refers to the ability to analyze tens, hundreds, or even thousands of samples per day, either across a laboratory workflow or on a single analytical system. Achieving this requires more than just a fast method. It depends on reliable instrumentation, automation, sufficient sample capacity, and smart system design that minimizes idle time between runs.In this article, we look at the key requirements for high-throughput HPLC analysis and how they are addressed in the <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/2371">HTQC system</a>.<h4>Speed</h4>High-throughput HPLC workflows typically rely on short methods. This includes both the chromatographic runtime and the cycle time of the injection module.With the HTQC system, fast gradient applications up to 1200 bar can be implemented using two integrated UHPLC high-pressure gradient pumps.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_1_2_HPG_pumps_of_HTQC_system_left_P_8_1_L_max_pressure_1240_bar_right_P_6_1_L_max_pressure_1000_bar_4d4873ff2f.jpg" alt="KNAUER: Fig. 1–2 HPG pumps of HTQC system, left: P 8.1L (max. pressure 1240 bar), right: P 6.1L (max. pressure 1000 bar)" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_1_2_HPG_pumps_of_HTQC_system_left_P_8_1_L_max_pressure_1240_bar_right_P_6_1_L_max_pressure_1000_bar_4d4873ff2f.jpg 245w," sizes="100vw" width="1266" height="386">We will not discuss the full details of transferring classical HPLC methods to fast, high-resolution UHPLC methods here, but UHPLC implementation can dramatically reduce total analysis time.Let’s use a hypothetical example. Imagine Giorgia, a randomly chosen name, working in pharmaceutical quality control in 1998. She must have travelled back in time, because she would have been too young to work in a lab then, but the example still works. With a classical HPLC method, each sample takes approximately 75 minutes, including equilibration, analysis, and backflushing of a 250 × 4.6 mm ID column. This type of method has been common in QC laboratories around the world. During an eight-hour working day, Giorgia can analyze around six samples.Now let’s transfer the same method to UHPLC. The improvement is substantial. Analysis time, equilibration time, and backflushing time are all reduced to under six minutes per sample. Giorgia can now process around 90 samples in one working day.You may wonder why the HTQC system requires two UHPLC gradient pumps. We will come back to that shortly.The next way to increase speed is to reduce injector cycle time. Injection procedures and washing steps can sometimes take a significant amount of time. This is where the LH 8.1 liquid handler becomes important.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_3_KNAUER_LH_8_1_Liquid_Handler_77ab506ca6.webp" alt="KNAUER: Fig. 3 KNAUER LH 8.1 Liquid Handler" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_3_KNAUER_LH_8_1_Liquid_Handler_77ab506ca6.webp 129w," sizes="100vw" width="800" height="971">The LH 8.1 supports overlapped injections. This means that the next injection can already be prepared while the current analysis is still running. Necessary cleaning steps of the injection system are still maintained, but idle time is reduced.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_4_Schematic_buildup_of_injections_with_and_without_overlapped_injections_af089ba652.webp" alt="KNAUER: Fig. 4 Schematic buildup of injections with and without overlapped injections" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_4_Schematic_buildup_of_injections_with_and_without_overlapped_injections_af089ba652.webp 245w," sizes="100vw" width="1920" height="452">Let’s return to Giorgia. By using overlapped injections in her QC method, she saves about one minute per sample. This increases her capacity to approximately 105 samples per day.<h4>Sample Throughput</h4>A high-throughput system must also be able to handle and store a sufficient number of samples. Here, the LH 8.1 provides another major advantage. In the long-rail version, it can be equipped with up to three robotic coolers.With three coolers, each containing three drawers, the system can hold nine 10 × 13 sample trays. That means a total capacity of 1170 vials. The samples are also temperature controlled.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_5_6_Robotic_Cooler_with_two_10x6_trays_LH_8_1_887_version_with_two_Robotic_Coolers_855b10c2a3.jpg" alt="KNAUER: Fig. 5–6 Robotic Cooler with two 10x6 trays, LH 8.1 (887 version) with two Robotic Coolers" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_5_6_Robotic_Cooler_with_two_10x6_trays_LH_8_1_887_version_with_two_Robotic_Coolers_855b10c2a3.jpg 245w," sizes="100vw" width="1262" height="503">Combined with the low eluent consumption typical of UHPLC, this large sample capacity makes it possible to extend operation from an eight-hour workday to 24-hour operation.For Giorgia and her QC lab, this changes everything again. The same UHPLC method, including overlapped injections, can now run continuously around the clock. This allows approximately 320 samples to be processed per day.Is that enough? Maybe not. As the blog title suggests: we just can’t get enough.<h4>Automation</h4>In addition to a standard 6-port, 2-position injection valve, the HTQC system includes an additional valve. This special column-switching and backflushing valve enables two columns to be operated alternately within a single UHPLC system.While one column is used for analysis, the second column can be backflushed and equilibrated in the reverse flow direction at the same time. This is particularly useful for reducing matrix effects, which are often encountered in QC laboratories when complex sample matrices are analyzed. It also helps reduce overall method runtime.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_7_Exemplary_flow_scheme_of_special_column_switching_valve_d837a71117.webp" alt="KNAUER: Fig. 7 Exemplary flow scheme of special column switching valve" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_7_Exemplary_flow_scheme_of_special_column_switching_valve_d837a71117.webp 127w," sizes="100vw" width="735" height="905"><h4>Parallel Processing</h4>Remember the earlier question: why does the system use two UHPLC gradient pumps?The reason is now clear. The second gradient pump is required to backflush one column while the other column is connected to the analytical flow path through the special switching valve.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_8_Schematic_illustration_of_column_cleaning_equilibration_and_analysis_with_special_backflush_valve_eae2e6f705.webp" alt="KNAUER: Fig. 8 Schematic illustration of column cleaning, equilibration and analysis with special backflush valve" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_8_Schematic_illustration_of_column_cleaning_equilibration_and_analysis_with_special_backflush_valve_eae2e6f705.webp 245w," sizes="100vw" width="1920" height="281">Giorgia immediately ordered a second UHPLC pump and the special valve for her QC lab. She now has a complete HTQC system and is very pleased with the result.Why? Let’s calculate it one final time. With all automation features in place, Giorgia can clean one column while the other column analyzes a sample. This enables her to process an impressive 600 samples per day.Compared with the classical HPLC method she used in 1998, the daily sample throughput has increased from six samples to 600 samples. That is a 100-fold increase.<h4>Summary</h4>We started with a question, so let’s end with one too: what steps increased the throughput?First, the method was scaled down from classical HPLC to a fast UHPLC approach. Then, a second pump and a special column-switching and backflushing valve were added to the UHPLC setup. Together with the <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/1454">LH 8.1 liquid handler</a> and its exceptional sample capacity, the HTQC system becomes a flexible and powerful configuration for high-throughput analysis.The system can also be coupled to nearly any detector used in HPLC. Because of its ability to operate at very high speed, it is especially well suited for mass spectrometric methods.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_9_Complete_flow_scheme_of_HTQC_system_with_highlighted_system_components_edef36cb42.webp" alt="KNAUER: Fig. 9 Complete flow scheme of HTQC system with highlighted system components" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_9_Complete_flow_scheme_of_HTQC_system_with_highlighted_system_components_edef36cb42.webp 161w," sizes="100vw" width="800" height="775"><blockquote>For further information on this topic, please contact our authors: kramer@knauer.net, m.myrach@knauer.net</blockquote>

Introducing Our System Solution for High Throughput Quality Control – HTQC

Our Library never stops expanding. What are the most recent contributions to LabRulezLCMS Library in the week of 21st September 2026? Check out new documents from the field of liquid phase, especially HPLC and LC/MS techniques!<blockquote>👉 <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library">SEARCH THE LARGEST REPOSITORY OF DOCUMENTS ABOUT LCMS AND RELATED TECHNIQUES</a></blockquote><blockquote>👉 Need info about different analytical techniques? Peek into <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library">LabRulezGCMS</a> or <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/library">LabRulezICPMS</a> libraries.</blockquote>This week we bring you application notes by KNAUER and Shimadzu, technical note by Thermo Fisher Scientific and poster by Waters Corporation / SOFT!<h3>1. KNAUER: Precise Catechin Profiling in Various Types of Tea</h3><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/pdf/VFD_0198_knauer_precise_catechin_profiling_in_various_types_of_tea_d607cde5ba.pdf">Full PDF for download</a></li></ul>Fresh tea leaves contain high concentrations of catechins, which have many beneficial properties. These include antioxidant, anti-inflammatory as well as antimicrobial effects, and it is even claimed that they have the potential to prevent cancer [1]. In addition, the taste and mouthfeel of a tea strongly depend on its catechin profile. The catechin content of tea leaves varies based on cultivation area, age and variety, as well as on how they are fermented, processed and packed. Therefore, the catechin content is an important marker for the quality of tea.&nbsp;The analysis of catechins can be challenging. The structural similarity of the catechin isomers and other closely related compounds result in similar behavior and a difficult separation (Fig. 1). Catechins possess many phenolic hydroxyl groups, which are prone to secondary interactions, like hydrogen bonding. Classical as well as highly endcapped C18 columns offer only limited retention and selectivity for catechins. Therefore, the KNAUER column portfolio has been expanded to include a pentafluorophenyl (PFP)-modified stationary phase (Eurospher II 100-3 PFP column 50 x 2 mm). It offers optimal separation of the catechins based on hydrophilic, hydrophobic and π-π-interactions. The column withstands acidic eluents (pH 1.5–10) as well as 100 % aqueous conditions, which are beneficial for the retention of hydrophilic compounds. The KNAUER Gradient Prediction Tool assisted with the challenging method development which is described in detail in the TechNote “The Gradient Prediction Tool: Method Development for the Separation of Catechins from Tea”. Here, the application of the optimized method for the identification and quantification of catechins in tea extracts is shown. The seven compounds specified in ISO-14502-2 (2005), as well as two additional catechins known as (+)-gallocatechin and (–)-gallocatechin gallate, were quantified.<h4>MATERIAL AND METHODS</h4><ul><li>Pump: <a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/all/products/2374">P8.1L</a>; high pressure gradient&nbsp;</li><li>Liquid Handler: <a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/all/products/1454">LH 8.1L </a>With FastWash station, and Robotic cooler. Loop: 20 µl.</li><li>Thermostat: <a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/all/products/2376">CT 2.1L&nbsp;</a></li><li>Detector: <a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/all/products/2424">DAD 6.1L&nbsp;</a></li><li>Flow cell: Analytical LightGuide flow cell (50 mm, 6 µl)&nbsp;</li><li>Software: ClarityChrom 10.1</li></ul><h4>CONCLUSION&nbsp;</h4>The application note demonstrates the reliable separation and quantification of catechins and caffeine in tea extracts using the new KNAUER PFP column. Using an optimised gradient predicted with the KNAUER Gradient Prediction Tool, nine tea-related compounds were separated in under 23 minutes. The tested tea samples showed different catechin content highlighting how strongly tea composition depends on the product type and processing.<h3>2. Shimadzu: New Derivatization Method for Quantitative Analysis of Δ⁹-THC-COOH in Urine</h3><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/pdf/an_01_01215_en_c98174629b.pdf">Full PDF for download</a></li></ul><h5>User Benefits</h5><ul><li>The risk of limited availability of stable isotope-labeled standards can be avoided by synthesizing internal standards through derivatization.&nbsp;</li><li>The derivatizing agent IPPAH and its corresponding stable isotope IPPAH-d6 can be synthesized easily and inexpensively from acetone (or acetone-d6).&nbsp;</li><li>This approach achieves sufficient sensitivity and quantitative accuracy for the determination of Δ⁹-THC-COOH in urine.</li></ul>In Japan, the Cannabis Control Act and the Narcotics and Psychotropics Control Act were amended in December 2024. While cannabis was legalized for industrial and medical uses, stricter cannabis regulations have been enacted to prevent harm from its abuse. The primary psychoactive cannabinoid, delta-9-tetrahydrocannabinol (Δ⁹-THC), is extensively metabolized in the body and is excreted mainly in urine and feces as 11-nor-9-carboxy-THC (Δ⁹-THC-COOH) and its glucuronide conjugates. Consequently, Δ⁹-THC-COOH must be analyzed to confirm cannabis use. For LC-MS/MS quantitation, the stable isotope-labeled internal standard Δ⁹-THC-COOH-d3 is commonly used to correct for matrix effects. However, most suppliers of stable isotope standards are located in the U.S., making these standards difficult to obtain due to import procedures. Furthermore, there may be additional importrelated supply risks for stable isotope standards in the future.&nbsp;This Application News describes a technique for quantitating Δ⁹-THC-COOH using an internal standard that is synthesized easily and inexpensively by derivatization with IPPAH (1- isopropylpiperidine carboxylic acid hydrazide), which characteristically reacts with carboxyl groups, and its corresponding stable isotope IPPAH-d6.<h4>Analysis Conditions&nbsp;</h4>LC-MS/MS analysis conditions are shown in Table 1. The <a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/lcms/library?mainauthorItems=1&amp;search=Nexera+XR">Nexera XR</a> and <a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/lcms/library?mainauthorItems=1&amp;search=LCMS-8050">LCMS-8050 systems</a> were used.<h4>Conclusion&nbsp;</h4>Derivatization with IPPAH and its stable isotope analog, IPPAHd6, enabled the simple and inexpensive preparation of an internal standard. This approach provides sufficient sensitivity and accuracy for the determination of Δ⁹-THC-COOH in urine. Most stable isotope-labeled standards are supplied by foreign manufacturers, creating a risk of delays or difficulties in procurement due to import/export regulations. By synthesizing the internal standard through derivatization, this risk can be minimized.<h3>3. Thermo Fisher Scientific: High-throughput quantitative proteomics with Evosep Eno and the Orbitrap Astral Zoom Mass Spectrometer</h3><ul><li>Technical note</li><li><a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/pdf/tn_004544_ov_astralzoom_evosepeno_htp_proteomics_tn004544_na_en_f31db9084e.pdf">Full PDF for download</a></li></ul>High-throughput proteomics is a critical enabling technology for large clinical studies, high-content drug screening, and systems biology research, allowing for comprehensive and quantitative analysis of complex proteomes across large sample cohorts within practical timeframes. As biological and translational studies expand in scale and complexity, the ability to generate deep and reproducible proteome measurements across thousands of samples has become increasingly essential for robust biomarker discovery, network-level systems modeling, and downstream analyses. In these contexts, accurate and precise protein quantitation must be maintained without sacrificing throughput, placing stringent demands on the performance and robustness of both LC instruments and mass spectrometers.&nbsp;To meet these increasing analytical demands, the Evosep Eno was developed as a high‑throughput LC system that combines robustness, ease of use, and highly reproducible chromatography. It offers six standardized methods: 30, 60, 100, 200, 300, and 500 samples per day (SPD), allowing users to select the throughput that aligns best with their study goals.1 These predefined methods ensure consistent gradient delivery, highly stable retention times, and reproducible system performance across instruments and laboratories.2 By reducing LC‑related variability and simplifying everyday operation, the Evosep Eno offers a strong and consistent foundation for large‑scale proteomics workflows, particularly those relying on short gradients and high reproducibility required for downstream quantitative analysis.<h4>Experiment</h4><h5>Instrumentation&nbsp;</h5><ul><li><a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/lcms/library?mainauthorItems=291&amp;search=evosep+eno">Evosep Eno&nbsp;</a></li><li><a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/all/products/1959">Orbitrap Astral Zoom Mass Spectrometer&nbsp;</a></li><li><a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/all/products/2464">Thermo Scientific™ EASY-Spray™ Ion Source&nbsp;</a></li><li>Evosep™ Pod for EASY-Spray Ion Source</li></ul><h5>Software&nbsp;</h5><ul><li>Biognosys Spectronaut® 19.7 software&nbsp;</li><li>MacCoss Lab Software Skyline-Daily V25.1</li></ul><h4>Summary&nbsp;</h4><h5>Seamless and easy integration for high-throughput proteomics&nbsp;</h5>Evosep Eno integrates seamlessly with the Orbitrap Astral Zoom Mass Spectrometer, supported by EASY-Spray source-compatible columns, emitters, and the Evosep Pod column oven for a simple, streamlined, high-throughput workflow.&nbsp;<h5>Deep proteome coverage at 500 SPD&nbsp;</h5>Optimized MS parameters for the standard 500 SPD Evosep Eno gradient enabled identification of more than 6,500 protein groups and 71,000 modified peptides from three replicates of 200 ng Pierce HeLa Digest/PRTC Standard.<h5>Reproducible quantitation across standard gradients&nbsp;</h5>Across all standard Evosep Eno gradients, the workflow delivered highly reproducible label-free quantification, with median protein group %CVs at or below 5.2%, while identifying more than 10,500 protein groups and 190,000 modified peptides from five replicates of 200 ng Pierce HeLa Digest/PRTC Standard at 30 SPD.&nbsp;<h5>Robust chromatography at ultra-high throughput&nbsp;</h5>Chromatographic performance remained stable and robust at 500 SPD, with nearly 100 consecutive runs showing PRTC retention time standard deviations below 0.4 seconds and a median of 6 DPPP.&nbsp;<h5>Strong linearity for confident quantitation&nbsp;</h5>Quantitative performance remained strong at 500 SPD, with PRTC peptides showing excellent linearity across the active gradient (R² &gt;0.98) when spiked from attomolar to femtomolar concentrations.<h3>4. Waters Corporation / SOFT: COMPARATIVE EVALUATION OF HIGH RESOLUTION MASS SPECTROMETRY ACQUISITION STRATEGIES FOR THE DETECTION AND ANALYSIS OF ILLICIT DRUG SUBSTANCES</h3><ul><li>Poster</li><li><a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/pdf/720009592_0bd2b5ee6a.pdf">Full PDF for download</a></li></ul><div><div><section><div><div><div><div><div><div>The poster compares two high-resolution time-of-flight mass spectrometry acquisition strategies for toxicology screening: targeted Tof-MRM and data-independent Tof-MSE, both implemented on a Waters <a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/all/products/1148">Xevo MRT MS</a> coupled to an <a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/all/products/199">ACQUITY UPLC I-Class FTN PLUS System</a>. The aim was to determine whether these approaches could meet routine service requirements for drug testing while also broadening the number of substances that can be detected beyond conventional targeted panels. Urine samples were prepared across a wide concentration range for 20 target analytes, and the methods were also applied to 20 anonymized authentic urine samples.Both workflows used a 15-minute LC separation on an <a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/all/products/1952">ACQUITY HSS C18 column</a> under positive electrospray ionization. In the targeted Tof-MRM mode, selected precursor ions were isolated and fragmented, with quantifier and qualifier ions monitored for sensitive quantitative analysis. In contrast, Tof-MSE operated in a data-independent mode, alternating between low and elevated collision energies to collect accurate-mass precursor and fragment-ion information for a broad range of compounds. Data were processed in the waters_connect platform using MS Quan for Tof-MRM and UNIFI with the Waters Toxicology Library, containing more than 2,100 drugs and metabolites, for Tof-MSE.The targeted Tof-MRM method provided the highest sensitivity, with limits of detection ranging from 0.05 to 0.5 ng/mL in fortified urine. The broader Tof-MSE workflow achieved LODs of approximately 0.5 to 5 ng/mL. When both strategies were applied to authentic urine samples, they showed excellent qualitative agreement. Importantly, Tof-MSE detected additional compounds outside the predefined target panel, including commonly encountered medications, benzodiazepines, antidepressants, and illicit drug substances that would not have been captured by the targeted method alone.Overall, the study shows that Tof-MRM can deliver sensitivity comparable to conventional tandem-quadrupole LC-MS/MS for targeted urinary drug analysis, while Tof-MSE adds broader sample characterization and retrospective screening capability. Used together, the two acquisition strategies provide a flexible approach that combines sensitive quantification of predefined analytes with expanded screening for unexpected or previously untargeted drug substances in complex biological samples.</div></div></div></div></div></div></section></div></div>

News from LabRulezLCMS Library - Week 39, 2026

News from LabRulezLCMS Library - Week 42, 2026

<h3>A look at how HPLC injection principles have evolved</h3>Summer is approaching, so it is time to get your bicycle ready again. But the tyres are flat, and you start pumping them up. At first, inflating them is easy. As the pressure approaches the target value of around 4 bar, however, every additional stroke requires noticeably more force. Adding more air to an already pressurized system becomes increasingly difficult.High-Performance Liquid Chromatography (HPLC) faces a comparable challenge, only on a much more demanding scale. Instead of pressures around 4 bar, modern HPLC and UHPLC systems may operate above 1,000 bar. And instead of air, they handle liquid mobile phases, often together with chemically hazardous substances. Introducing a sample into such a pressurized environment is therefore far from straightforward. The transition from early septum-based injection methods to automated sample introduction took decades, and development continues today as laboratories seek shorter cycle times, reduced sample consumption, lower carryover, and better data quality.<h4>The beginnings of HPLC injection</h4>By the 1950s, gravitational liquid chromatography had already been used for almost half a century. Its further development, however, was limited by two major technical challenges: the introduction of smaller stationary-phase particles and the need to operate at much higher pressures.Around 1965, Csaba Horváth and his colleagues successfully addressed these limitations by developing one of the first HPLC systems. Since then, continuous technical innovation has transformed HPLC into one of the most robust, precise, and widely used separation techniques in analytical laboratories.In the earliest HPLC systems, samples were introduced manually. Analysts either injected directly into a pressurized system or temporarily stopped the mobile-phase flow to introduce the sample. Neither approach offered particularly good reproducibility or quantitative precision. The growing demand for reliable analytical results therefore created a clear need for standardized and more controlled injection technology.<h4>The invention of the six-port rotary valve</h4>A major breakthrough came with the development of the multi-port rotary sampling valve in the late 1970s. This principle became the foundation of modern HPLC injection systems.The most common configuration is the six-port valve with a defined sample loop. Its stator contains six ports: two connect to the chromatographic system, two are used for sample introduction and waste, and the remaining two connect to the sample loop. The actual switching of flow paths is performed by a rotor seal pressed against the back of the stator. Precisely manufactured grooves in the rotor determine how the ports are interconnected.The system operates in two main positions: LOAD and INJECT.In the LOAD position, the analyst fills the sample loop manually with a syringe while the mobile phase continues to flow directly from the pump to the analytical column. Once the valve is rotated into the INJECT position, the filled sample loop becomes part of the high-pressure mobile-phase pathway and the sample is swept onto the column.This principle provides a defined and comparatively safe way of introducing the sample without interrupting the chromatographic flow.Today, KNAUER offers a broad portfolio of manually and electrically actuated valves, including two-position, multiposition, and special-purpose designs. The AZURA V 4.1 valve series can be integrated into modern chromatographic systems and adapted to a variety of applications.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_1_6_port_2_position_valve_Left_LOAD_Right_INJECT_Bottom_KNAUER_AZURA_V_4_1_valve_ec0dd2b773.webp" alt="KNAUER: Fig. 1 - 6-port 2-position valve. Left: LOAD. Right: INJECT. Bottom: KNAUER AZURA V 4.1 valve." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_1_6_port_2_position_valve_Left_LOAD_Right_INJECT_Bottom_KNAUER_AZURA_V_4_1_valve_ec0dd2b773.webp 203w," sizes="100vw" width="1024" height="785">Despite the major improvement represented by rotary injection valves, manual injection soon became a limitation as HPLC gained popularity in routine analytical laboratories.Every sample still required an operator to physically rotate the valve. As sample numbers increased, this significantly limited laboratory throughput. Injection quality was also influenced by operator technique. Differences in sample-loop filling and the exact timing of valve switching could affect reproducibility.Automation therefore became the logical next step.<h4>Injection principles used in autosamplers</h4>Autosamplers emerged during the mid-1980s, while the injection valve remained the central element of the design. As an interesting historical note, KNAUER had already become the first European manufacturer of modular HPLC systems in 1976.An autosampler is an electrically operated injection system equipped with a sample storage area, usually designed for vials or multiwell plates. Its performance can be evaluated using several important parameters.<ul><li>Precision describes how reproducibly the system performs repeated injections. It is commonly assessed using the relative standard deviation (RSD) of peak areas or retention times from multiple measurements, often with five replicate injections.</li><li>Linearity expresses whether the detector response changes proportionally with the injected sample volume. Ideally, increasing the injection volume step by step should produce a proportional increase in signal, with an R² value close to 1.</li><li>Carryover occurs when traces of an analyte remain on the needle, within the valve, or inside the sample loop and subsequently contaminate the next analysis. Washing the needle and injection pathway can reduce this effect, although more extensive washing usually increases the total cycle time.</li><li>Cycle time is another critical factor. Shorter cycles allow laboratories to process more samples per day and reduce both instrument occupancy and labor requirements. However, reducing cycle time can conflict with the need for additional washing steps to control carryover.</li></ul>Modern autosamplers generally use one of three fundamental injection concepts.<h4>Pushed-loop injection</h4>The pushed-loop design is probably the closest automated equivalent of traditional manual loop injection.In the LOAD position, the sample is first aspirated into a dedicated aspiration capillary and temporarily stored outside the main chromatographic flow path. The injection needle then moves to a low-pressure needle port and pushes the sample into the bypassed sample loop.After the loop has been filled, the valve switches to the INJECT position. The sample loop is then connected to the mobile-phase stream from the pump, and the analyte is transported toward the analytical column.KNAUER's <a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/all/products/1454">Liquid Handler LH 8.1</a> uses this straightforward pushed-loop principle and can be configured for high-throughput applications. Its large sample capacity and overlapped injection capabilities support automated workflows with high sample numbers.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_2_Pushed_loop_design_Left_LOAD_Right_Sample_introduction_PUSH_Bottom_Left_INJECT_Bottom_Right_KNAUER_Liquid_Handler_LH_8_1_4d3df5b895.webp" alt="KNAUER: Fig. 2 Pushed-loop design. Left: LOAD. Right: Sample introduction (PUSH). Bottom Left: INJECT. Bottom Right: KNAUER Liquid Handler LH 8.1." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_2_Pushed_loop_design_Left_LOAD_Right_Sample_introduction_PUSH_Bottom_Left_INJECT_Bottom_Right_KNAUER_Liquid_Handler_LH_8_1_4d3df5b895.webp 243w," sizes="100vw" width="1920" height="1235"><h4>Pulled-loop injection</h4>The pulled-loop design approaches sample introduction from the opposite direction.Instead of using a separate aspiration capillary, the sample loop itself is used for aspiration. During the LOAD phase, the analyte is drawn directly into the loop. When the valve changes to the INJECT position, the sample loop becomes part of the main chromatographic flow path.At the same time, the injection syringe can move to a wash position to reduce residual contamination.Because the design eliminates the need for a low-pressure needle port and additional aspiration capillaries, it reduces the number of potential leakage points and can lower operating and maintenance costs.KNAUER uses this robust and cost-efficient concept in the <a target="_blank" rel="noopener noreferrer" href="https://labrulez.com/en-us/all/products/2375">AZURA AS 6.1L autosampler</a>. The instrument is available in several configurations, including temperature-controlled, biocompatible, preparative, and UHPLC versions.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_3_Pulled_loop_design_Left_LOAD_Right_INJECT_Bottom_KNAUER_autosampler_AZURA_AS_6_1_L_43a4e8c44a.webp" alt="KNAUER: Fig. 3 - Pulled-loop design. Left: LOAD. Right: INJECT. Bottom: KNAUER autosampler AZURA ​AS 6.1L." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_3_Pulled_loop_design_Left_LOAD_Right_INJECT_Bottom_KNAUER_autosampler_AZURA_AS_6_1_L_43a4e8c44a.webp 245w," sizes="100vw" width="1024" height="639"><h4>Full-loop, partial-loop, and µL pickup modes</h4>Pulled-loop systems typically provide several injection modes, each offering a different compromise between precision, flexibility, and sample consumption.<ul><li>In full-loop injection, the entire sample loop is filled. This generally provides the highest precision and reproducibility because the injected volume is defined by the physical volume of the loop. The disadvantage is relatively high sample consumption, since the capillary between the needle and the loop must be flushed and the loop itself is usually overfilled to ensure complete filling.</li><li>Partial-loop injection provides greater flexibility because different injection volumes can be selected without changing the sample loop. This approach is useful for applications such as dilution series. However, the tubing between the injection needle and the loop still needs to be flushed, resulting in additional sample consumption.</li><li>The µL pickup mode is designed to minimize sample loss. Only the exact amount required for injection is aspirated, while transport solvent is used to move the sample through the tubing. This makes µL pickup particularly attractive when sample availability is limited or when precious samples are being analyzed.</li></ul>Even with these designs, there remained room for improvement. The next development step focused on reducing sample consumption and carryover while shortening cycle times and maintaining high injection precision.<h4>Split-loop injection</h4>The modern split-loop design differs fundamentally from the previous concepts because the needle seat is located directly in the high-pressure flow path.In the LOAD position, the system flow path is divided while the sample is aspirated directly into the injection needle. The outside of the needle can subsequently be washed to remove potential contamination before the needle enters the high-pressure seat.At first glance, this design may resemble the pushed-loop configuration. The critical difference, however, is that the sample needle itself becomes part of the chromatographic flow path.The needle seat therefore operates under full system pressure. In modern UHPLC applications, this can exceed 1,000 bar. Consequently, the needle and seat must form a highly precise high-pressure seal capable of maintaining reliability over many injection cycles.Once the needle is positioned in the seat, the valve switches to INJECT and the sample becomes fully integrated into the system flow path.Because the mobile phase continuously passes through the needle during the chromatographic run, the internal needle surface is extensively rinsed with eluent. In many cases, this eliminates the need for additional internal needle-washing steps and contributes to shorter cycle times.With the AZURA AS 8.1L, KNAUER introduces a modern autosampler based on this state-of-the-art split-loop principle for HPLC and UHPLC applications.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Fig_4_Split_loop_design_Left_LOAD_Right_INJECT_Bottom_KNAUER_autosampler_AZURA_AS_8_1_L_ff89233502.webp" alt="KNAUER: Fig. 4 Split-loop design. Left: LOAD. Right: INJECT. Bottom: KNAUER autosampler AZURA AS 8.1L." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Fig_4_Split_loop_design_Left_LOAD_Right_INJECT_Bottom_KNAUER_autosampler_AZURA_AS_8_1_L_ff89233502.webp 234w," sizes="100vw" width="1024" height="684">The split-loop approach can substantially reduce sample loss, shorten cycle times, minimize carryover, and provide high injection precision.However, these advantages come with slightly greater mechanical complexity. For reliable long-term operation, the high-pressure sampling needle and the corresponding needle seat should be maintained regularly, typically on an annual basis.<h4>Pulled-loop versus split-loop</h4>Both injection concepts have advantages, and the preferred design depends on the analytical application.The AZURA AS 6.1L pulled-loop system offers greater mechanical simplicity and flexibility and generally places lower demands on maintenance. It also benefits from a comparatively low dwell volume.The AZURA AS 8.1L split-loop system, on the other hand, provides advantages in sample conservation, cycle time, carryover performance, and injection precision.<div><div><div><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Tab_1_Brief_site_by_site_comparison_of_KNAUER_s_AS_6_1_L_pulled_loop_and_AS_8_1_L_split_loop_c28ce01ff3.jpg" alt="KNAUER: Tab. 1 Brief site-by-site comparison of KNAUER's AS 6.1L (pulled-loop) and AS 8.1L (split-loop)." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Tab_1_Brief_site_by_site_comparison_of_KNAUER_s_AS_6_1_L_pulled_loop_and_AS_8_1_L_split_loop_c28ce01ff3.jpg 245w," sizes="100vw" width="1061" height="381"></div></div></div>The choice therefore depends on whether the priority is mechanical simplicity and flexibility or maximum efficiency in terms of sample consumption, speed, and injection performance.<h4>Final thoughts</h4>Sample injection may appear to be one of the simplest steps in an HPLC workflow, but its development shows how much engineering is required to introduce a few microliters of sample accurately and reproducibly into a pressurized chromatographic system.From early manual injection through six-port rotary valves and the first autosamplers to modern pushed-loop, pulled-loop, and split-loop designs, each generation has addressed specific limitations of the previous approach.The continuing evolution of injection technology reflects broader trends in liquid chromatography: laboratories expect higher throughput, better reproducibility, lower carryover, reduced sample consumption, and increasingly reliable unattended operation.What appears today as a routine movement of a needle and switching of a valve is therefore the result of decades of development in chromatography, mechanical engineering, fluidics, and automation.

A glimpse into the evolution of HPLC injection principles

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Based in Berlin, KNAUER is a medium-sized, owner-managed company that has been serving the sciences since 1962. We develop and manufacture scientific instruments of superior quality for liquid chromatography, including: Analytical HPLC/UHPLC, Preparative HPLC, Fast protein liquid chromatography (FPLC), Multi-column chromatography/Simulated moving bed (SMB) chromatography. High pressure dosing, in-line detection systems, and osmometry are additional business areas.

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