<p><strong>Matrix effects significantly limit accurate nanoparticle sizing in single-particle ICP-MS, often causing signal attenuation and size underestimation. This study systematically evaluates matrix-induced biases and reports up to 10 nm underestimation of Ag nanoparticle sizes due to 30–50% signal loss.</strong></p><p>To overcome these challenges, a novel online internal standard calibration strategy was developed using multielement detection and nonanalyte elements (Pd, Au) as internal standards. Simultaneous measurement of analyte and standards enabled correction of signal response and nebulization efficiency within a single run. The optimized approach provided accurate particle size determination in simulated and real matrices, extending SP-ICP-MS applicability to complex environmental and biological samples.</p><blockquote><h4><strong>The original article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c06975"><strong>A Simple Online Internal Standard Calibration Strategy for Single-Particle Inductively Coupled Plasma Mass Spectrometry Based on Multielement Analysis</strong></a></h4><p>Xiangwei Tian, Ying Wang, Peijie Yang, Dingyi Wang, Yanwei Liu, Yingying Guo, Yuning Hu*, Xiaoyan Zhang*, Ligang Hu, Yongguang Yin*, Yong Cai, and Guibin Jiang</p><p>Anal. Chem. 2025, 97, 51, 28139–28147</p><p><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1021/acs.analchem.5c06975">https://doi.org/10.1021/acs.analchem.5c06975</a></p><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/"><strong>CC-BY 4.0</strong></a></h6></blockquote><p><strong>Selected sections from the article follow. Formats and hyperlinks were adapted from the original.</strong></p><div><p>Nanoparticles (NPs) are ubiquitous in environmental and biological systems. <a href="javascript:void(0);">(1)</a> In the environment, billions of tons of natural NPs are formed annually through biogeochemical processes. <a href="javascript:void(0);">(1)</a> Engineered NPs are widely utilized in industrial, medical, and consumer products and inevitably released into the environment. <a href="javascript:void(0);">(2)</a> In biological systems, NPs can be endogenously formed <a href="javascript:void(0);">(3)</a> or acquired from environmental exposure. <a href="javascript:void(0);">(4)</a> Functional NPs can also be intentionally delivered into biological systems as probes or drugs. <a href="javascript:void(0);">(5−7)</a> Variations in physicochemical properties of NPs, such as size and elemental composition, can influence their distribution patterns and effects within environmental and biological systems. <a href="javascript:void(0);">(8,9)</a> Therefore, it is of great significance to resolve particle heterogeneity at the single-particle level. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS), with its high-throughput and sensitive capabilities for elemental and isotopic analysis, plays a key role in single-particle analysis. <a href="javascript:void(0);">(10,11)</a></p><p>Environmental particles always exist in complex or unknown matrices, such as ice cores, <a href="javascript:void(0);">(12)</a> wastewater, <a href="javascript:void(0);">(13)</a> and seawater. <a href="javascript:void(0);">(14)</a> Biological matrices are even more intricate, typically containing high concentrations of inorganic salts and organic matter. Matrix effects pose significant challenges for SP-ICP-MS analysis of environmental and biological samples. <a href="javascript:void(0);">(15)</a> Matrix effects on ICP-MS are generally categorized into spectral and nonspectral interferences. <a href="javascript:void(0);">(15)</a> Spectral interferences arise from isobaric overlaps or polyatomic ions (e.g., ArCl<sup>+</sup> from Cl<sup>–</sup> interfering with <sup>75</sup>As detection), which can often be eliminated using collision/reaction cell technique. <a href="javascript:void(0);">(16)</a> Nonspectral interferences refer to matrix-induced changes in signal intensity. <a href="javascript:void(0);">(17)</a> For instance, NaCl can suppress signal intensity, whereas low concentrations of methanol may lead to signal enhancement. Changes in signal intensity further contribute to errors in mass/size measurement. It was reported that a 4.5 g L<sup>–1</sup> NaCl matrix caused underestimation of As(0) NP and Ag NP sizes by 28% and 41%, respectively, while a 2% methanol matrix resulted in overestimations of approximately 6% and 20%. <a href="javascript:void(0);">(17)</a> Common strategies to address nonspectral interferences include sample dilution and matrix matching. <a href="javascript:void(0);">(15)</a> However, dilution pretreatments would greatly reduce the analytical throughput, and changes in matrix concentration may affect the properties or state of the analyte. In real-world samples, the matrices are always complex, making it difficult to prepare solutions with exactly the same composition for matrix matching. Isotope dilution analysis (IDA), which involves enriched isotopes of the analyte element for signal response correction, is another established approach. <a href="javascript:void(0);">(18−20)</a> Nevertheless, due to strict requirements on matrix types, isotope properties, and analyte concentrations, IDA has limited applicability to real-world sample measurements. Furthermore, among the previously reported methods, the potential influence of the matrix on particle nebulization efficiency has not been fully considered, <a href="javascript:void(0);">(18,21,22)</a> leaving quantitative uncertainties. <a href="javascript:void(0);">(17)</a> The online droplet calibration method based on the microdroplet generator and ICP-time-of-flight (TOF)-MS considers matrix effects on both signal response and nebulization efficiency; <a href="javascript:void(0);">(15,23)</a> however, the technical barriers and high cost largely limit its broader adoption. Till now, due to the lack of practical calibration methods, the characterization of NPs in real matrices typically involves laborious extraction procedures. <a href="javascript:void(0);">(24,25)</a> A need exists to develop a simple and reliable calibration strategy suitable for the measurement in the original matrix.</p><p>In this study, we first systematically investigated the specific matrix effects on SP-ICP-MS and the underlying mechanisms based on the fundamentals of ICP-MS. The influence of time resolution on multielement detection was explored from multiple analytical perspectives. To address limitations of previous methods, we proposed a simple and reliable online internal standard calibration method, which largely eliminates matrix effects on size/mass determination by SP-ICP-MS. By utilizing the multielement detection mode, the signals of the analyte element(s) and internal standard elements can be monitored within the same analytical run, allowing for simultaneous correction of the response factor, nebulization efficiency, and time-dependent signal fluctuations. Notably, the novel calibration strategy involving the use a nonanalyte element as the internal standard for signal response calibration was developed and validated. The proposed method demonstrated high feasibility and reliability when applied to simulated real-world samples. It is also applicable to single-particle analysis using other types of ICP-MS (e.g., ICP-TOF-MS) and shows promise for application in single-cell ICP-MS analysis.</p><h4><strong>Experimental Section</strong></h4><h5><strong>SP-ICP-MS Analysis</strong></h5><p><a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/library?mainauthorItems=10&amp;search=7900+ICP-MS"><strong>Agilent 7900 ICP-MS</strong></a> (Agilent Technologies; Santa Clara, CA, USA) equipped with a quadrupole mass analyzer was used for SP-ICP-MS analysis. Instrument parameters are given in <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acs.analchem.5c06975/suppl_file/ac5c06975_si_001.pdf">Table S2</a>. The sample introduction system was composed of syringe pumps (Leifu Fluid; Baoding, China), a Mira Mist nebulizer (Burgener; Mississauga, Ontario, Canada), and a quartz dual-channel spray chamber (Agilent Technologies; Santa Clara, CA, USA) (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c06975#fig1">Figure 1</a>). The total sample flow rates were 300 μL min<sup>–1</sup> for all the experiments. Additionally, a more accessible introduction approach using the instrument’s integrated peristaltic pump was also tested (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acs.analchem.5c06975/suppl_file/ac5c06975_si_001.pdf">Figure S2</a>). Matrix effects on SP-ICP-MS analysis was investigated under the conventional single-element mode. The dwell time was 5 ms, with no stabilization time. The final inlet concentrations of Ag NPs and Au NPs were 50 ng L<sup>–1</sup> (∼4.2 × 10<sup>4</sup> particles mL<sup>–1</sup>) and 25 ng L<sup>–1</sup> (∼4 × 10<sup>4</sup> particles mL<sup>–1</sup>), respectively.</p><h4><strong>Results and Discussion</strong></h4><h5><strong>Matrix Effects on SP-ICP-MS and the Underlying Mechanisms</strong></h5><p>In the UPW matrix, the particle sizes determined by SP-ICP-MS (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c06975#fig2">Figure 2</a>A) were consistent with those measured by TEM (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acs.analchem.5c06975/suppl_file/ac5c06975_si_001.pdf">Figure S1A</a>). The most direct impact of matrix effects was observed as changes in the analyte signal intensity. Both the typical environmental and biological matrices we selected resulted in signal attenuation for the target elements. More pronounced signal attenuation was observed in the salt matrices with increasing concentration. Compared to measurements in UPW, the signal intensity of Ag NPs decreased by approximately 32% and 46% in DSW and PBS, respectively. Correspondingly, without matrix-matching correction, the particle sizes of Ag NPs were underestimated by approximately 12% and 19% in DSW and PBS, respectively (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c06975#fig2">Figure 2</a>A).</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Anal_Chem_2025_97_51_28139_28147_Figure_2_A_Particle_size_distribution_of_Ag_N_Ps_in_different_matrices_without_matrix_matching_f97e96e68c.jpeg" alt="Anal. Chem. 2025, 97, 51, 28139–28147: Figure 2. (A) Particle size distribution of Ag NPs in different matrices without matrix matching. The gray line and band denote the mean and standard deviation of the particle size determined by TEM. (B) Nebulization efficiency of Au NPs in different matrices. The letters on columns indicate the statistical difference obtained from one-way ANOVA test (p &lt; 0.05). (C) Signal intensity of standard Au NPs and AuCl4– solution in different matrices." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Anal_Chem_2025_97_51_28139_28147_Figure_2_A_Particle_size_distribution_of_Ag_N_Ps_in_different_matrices_without_matrix_matching_f97e96e68c.jpeg 245w," sizes="100vw" width="2100" height="537"></p><p>Matrix-induced attenuation/enhancement of signal intensity fundamentally arise from changes in the transport efficiency of the analyte. Transport efficiency is defined as a combination of several components (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c06975#fig1">Figure 1</a>): (i) the aerosol introduction efficiency (or nebulization efficiency) from the sample introduction system (typically comprising a nebulizer and spray chamber) to the ICP torch, as calculated using <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c06975#eq1">Equation 1</a>) or <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c06975#eq2">2</a>); (ii) the ionization efficiency of the analyte within the ICP torch; and (iii) the subsequent extraction and transport efficiency of ions from the sampling cone to the detector.</p><h5><strong>Validation of Online Internal Standard Calibration</strong></h5><p><a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c06975#fig4">Figure 4</a>A displays the Ag NP size distribution determined when the three inlet streams (Ag NP suspension, Au NP suspension, and Pd solution) were mixed at equal flow rates (3 × 100 μL min<sup>–1</sup>). For all the matrices, the measured particle sizes showed good agreement with the actual sizes determined by TEM. Note that since both the Au NP suspension and Pd solution were prepared using UPW, the matrix containing analyte Ag NPs would be diluted upon online mixing. For real-world samples, excessive dilution could potentially change sample properties and reduce measurement throughput. To prevent excessive dilution, the calibration results were further assessed under conditions of reduced internal standard flow rates (Ag NP flow rate: 260 μL min<sup>–1</sup>; internal standard flow rates: both 20 μL min<sup>–1</sup>) (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c06975#fig4">Figure 4</a>B). Furthermore, an offline spiking approach was also tested by adding both the internal standards directly into the sample suspension (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acs.analchem.5c06975/suppl_file/ac5c06975_si_001.pdf">Figure S7A</a>). The measured sizes also agreed well with the true values. For easier access and use, online mixing using a peristaltic pump was also tested and demonstrated to accurately determine the particle sizes (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acs.analchem.5c06975/suppl_file/ac5c06975_si_001.pdf">Figure S7B</a>). The results demonstrate that neither the introduction approach and the mixing ratio affected the calibration performance, suggesting the high reliability and flexibility of the internal standard calibration method.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Anal_Chem_2025_97_51_28139_28147_Figure_4_A_B_Particle_size_distribution_of_Ag_N_Ps_in_different_matrices_measured_by_the_internal_standard_calibration_method_4ca8d3833d.jpeg" alt="Anal. Chem. 2025, 97, 51, 28139–28147: Figure 4. (A, B) Particle size distribution of Ag NPs in different matrices measured by the internal standard calibration method. (A) Flow rates of the analyte and internal standards were all 100 μL min–1. (B) Flow rates of the analyte and internal standards were 260 and 20 μL min–1, respectively. (C, D) Particle size distribution of Ag NPs in natural seawater (C) and human urine (D) matrices measured by external standard calibration or online internal standard calibration method. the flow rates of the analyte and internal standards were 260 and 20 μL min–1, respectively. The gray lines and bands denote the mean and standard deviation of the particle size determined by TEM." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Anal_Chem_2025_97_51_28139_28147_Figure_4_A_B_Particle_size_distribution_of_Ag_N_Ps_in_different_matrices_measured_by_the_internal_standard_calibration_method_4ca8d3833d.jpeg 189w," sizes="100vw" width="1433" height="1184"></p><p>Further, we evaluated the performance of the proposed method in handling real biological (human urine) and environmental (natural seawater) matrices (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.analchem.5c06975#fig4">Figure 4</a>C and D). In addition to high salt concentrations, both matrices contain abundant organic matter, which pose challenges to accurate SP-ICP-MS analysis. Without matrix matching, the sizes of Ag NPs in both matrices were significantly underestimated. Particularly in seawater, the size was underestimated by nearly 20 nm. Using the online internal standard calibration, the median sizes of Ag NPs in diluted seawater and urine matrices were 58.9 and 58.5 nm, respectively, in close agreement with those determined by TEM. Notably, the sizes of Ag NPs in undiluted real matrices can also be accurately determined, facilitating the measurement of environmental particles in the original matrix.</p><h4><strong>Conclusions</strong></h4><p>In this study, we addressed the significant challenge of matrix effects in SP-ICP-MS for accurate mass/size determination in complex environmental and biological samples. We elucidated the specific matrix effects on nebulization efficiency, ionization efficiency, and ion transport. It was demonstrated that Ag NP signal intensity decreased by approximately 32% and 46% in DSW and PBS, respectively, leading to underestimated particle sizes (12% and 19%, respectively). To address these issues, we developed and validated an online internal standard calibration strategy employing multielement detection with nonanalyte elements as internal standards. By simultaneously monitoring analyte (Ag) and internal standard elements (Au for nebulization efficiency, Pd for response factor) within a single analytical run via the peak-hopping mode, we achieved real-time correction for matrix-induced variations. Optimized time-resolution conditions, particularly a 5 ms dwell time, ensured a high probability of complete event acquisition (81.8%) while minimizing particle overlapping. The measured sizes of Ag NPs in simulated (DSW and PBS) and real (natural seawater and human urine) matrices that showed good agreement with true values. The proposed method demonstrated high reliability and flexibility, regardless of the internal standard mixing ratio (e.g., 100:100:100 or 260:20:20 μL min<sup>–1</sup>), introduction approach, and sample dilution levels. In contrast to enriched isotope internal standards, which proved ineffective in anion-rich matrices due to chemical reactions, the presented nonanalyte internal standards offer enhanced adaptability across various matrices.</p><p>This reliable and flexible method significantly extends the applicability of SP-ICP-MS to direct analysis of complex samples without laborious pretreatments. The potential for the measurement in the original matrix is particularly meaningful for single-cell analysis, allowing direct analysis of living cells in biological matrices. Note that the theory and method validated with Ag NPs are also applicable to the quantification of other elements in particles or cells. As a simplified alternative to the established online microdroplet calibration, <a href="javascript:void(0);">(23)</a> the proposed strategy shows great promise in the integration of advanced ICP-TOF-MS platforms for simultaneous calibration of multiple analyte elements.</p></div>

A Simple Online Internal Standard Calibration Strategy for Single-Particle Inductively Coupled Plasma Mass Spectrometry Based on Multielement Analysis

News from LabRulezGCMS Library - Week 09, 2026

News from LabRulezLCMS Library - Week 09, 2026

<p><strong>Our Library never stops expanding. What are the most recent contributions to LabRulezICPMS Library in the week of 23rd February 2026? Check out new documents from the field of spectroscopy/spectrometry and related techniques!</strong></p><blockquote><p><span style="font-size:20px;">👉 </span><a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/library"><span style="font-size:20px;"><strong>SEARCH THE LARGEST REPOSITORY OF DOCUMENTS ABOUT SPECTROSCOPY/SPECTROMETRY RELATED TECHNIQUES</strong></span></a></p></blockquote><blockquote><p><strong>👉 Need info about different analytical techniques?</strong> Peek into <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library"><strong>LabRulezLCMS</strong></a> or <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library"><strong>LabRulezGCMS</strong></a> libraries.</p></blockquote><p>This week we bring you application notes by <strong>Agilent Technologies</strong>, <strong>Metrohm,</strong> <strong>Shimadzu </strong>and<strong> Thermo Fisher Scientific!</strong></p><h3><strong>1. Agilent Technologies: UV-Vis Spectroscopy for Quality Assessment of Paprika as per ASTA Method 20.1</strong></h3><p><strong>From sample prep to analysis using the </strong><a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/library?mainauthorItems=10&amp;search=Cary+3500"><strong>Agilent Cary 3500 Multicell UV-Vis</strong></a></p><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/labrulez-bucket-strapi-h3hsga3/an_paprika_uv_vis_cary_5994_8612en_agilent_d903914b39.pdf"><strong>Full PDF for download</strong></a></li></ul><p>Paprika is a widely used spice valued for its deep red color and characteristic flavor, contributing to its prominence in both culinary and commercial applications. As a high‑demand commodity produced from dried capsicum pods, paprika is subject to quality variation and adulteration, which can compromise product authenticity, consumer trust, and regulatory compliance. UV-Visible (UV-Vis) spectroscopy is a rapid, reproducible analytical technique for evaluating paprika quality by quantifying pigment concentration. In paprika, color intensity primarily arises from carotenoid compounds, and is commonly assessed using the ASTA Method 20.11 – a well-established industry standard that commercially grades paprika samples as a numerical ASTA color value.</p><p>In this application note, we used an <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/library?mainauthorItems=10&amp;search=Cary+3500"><strong>Agilent Cary 3500 Multicell UV-Vis spectrophotometer</strong></a> and <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/library?mainauthorItems=10&amp;search=UV+Workstation+software"><strong>Agilent Cary UV Workstation software</strong></a> to determine the ASTA color value of two commercial paprika samples. The measurements were performed in accordance with ASTA Method 20.1 for the determination of extractable color in capsicums and their&nbsp;oleoresins.</p><h4><strong>Results and discussion</strong></h4><h5><strong>Paprika samples' analysis&nbsp;</strong></h5><p>ASTA Method 20.1 measures the color intensity of paprika by extracting pigments with acetone and recording absorbance at 460 nm. The absorbance reading, along with sample weight is then used to calculate the ASTA color value. The ASTA color value is a crucial quality parameter for paprika and other spices, as it indicates the intensity and vibrancy of the red color, which is a key characteristic for consumers and food manufacturers. In this study, the two extracted paprika samples were each measured three times to produce triplicate results (Table 4). Sample 1 had a corrected ASTA color value of approximately 103, and sample 2 had a corrected ASTA color value of approximately 61, indicating a lower color intensity. The corrected ASTA color value was automatically generated in an easy-to-read table of values, and a scan report was automatically exported into a user-defined location.</p><h4><strong>Conclusion&nbsp;</strong></h4><p>The Agilent Cary 3500 Multicell UV-Vis spectrophotometer with Agilent Cary UV Workstation software enabled fast, reliable, and standardized quality assessment of paprika samples. Using the well-established industry method, ASTA 20.1, the Cary 3500 system provided precise quantification of carotenoid pigments, supporting grading categorization. The high-throughput multicell design of the Cary 3500 Multicell UV-Vis spectrophotometer allows simultaneous measurement of up to seven samples and a reference, improving efficiency and minimizing variability. The Cary UV Workstation software simplifies data acquisition and analysis with intuitive spectral features such as the End of sequence analysis tool, which can be applied automatically to any scan method, and spectra comparisons through the Load spectrum tool. From sample absorbance measurement to final reporting, the Cary 3500 system eliminated the need for manual data processing or external tools, minimizing complexity and facilitating confidence.</p><h3><strong>2. Metrohm: NIRS analysis of forages</strong></h3><p><strong>Multiparameter determination in a few seconds</strong></p><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/labrulez-bucket-strapi-h3hsga3/an_nir_131_download_2f897ff7f5.pdf"><strong>Full PDF for download</strong></a></li></ul><p>Forages are plants or parts of plants eaten by both livestock and wildlife. Forages provide bulk, help with weight maintenance, and combat several issues [1]. Alfalfa forage is high in protein—well-suited to promote muscle mass in beef cattle or to increase the production of dairy cows [2]. Alfalfa is also commonly used for horse feed. These animals require forages with good palatability along with high digestibility, intake potential, and protein levels, thus increasing the demand for alfalfa and other high-quality feeds. Farmers have responded by producing even higherquality alfalfa in recent years. Since forage quality depends on chemical, biological, and dynamic properties, both measured and calculated methods must be used. Standard alfalfa assays measure neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP), ash, moisture, and protein. For alfalfa pellets, the mean particle size is also important. Near-infrared spectroscopy (NIRS) offers rapid and reliable prediction of fat, moisture, crude protein, fiber, ash and starch in a few seconds and without sample preparation.</p><h4><strong>EXPERIMENTAL EQUIPMENT</strong></h4><p>Samples of alfalfa (including fresh alfalfa, alfalfa pellets, and alfalfa cubes) were analyzed on a <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/library?mainauthorItems=220&amp;search=NIR+Analyzer"><strong>Metrohm NIR Analyzer</strong></a>. All measurements were performed in reflection mode using the large cup. The samples were measured in rotation to collect spectral data from several areas. Spectral averaging of signals from several spots helped to reduce sample inhomogeneity. The reference values were measured according to ISO norms described at the end of this Application Note. Metrohm software was used for all data acquisition and prediction model development.</p><h4><strong>CONCLUSION&nbsp;</strong></h4><p>This Application Note demonstrates the feasibility to determine multiple key parameters of alfalfa forage with NIR spectroscopy. Several analytical methods are usually required to measure key quality parameters for forage (Table 4). NIRS forage analysis enables a highly accurate, cost-effective, and fast alternative.</p><h3><strong>3. Shimadzu: Analysis of Heavy Metals in Baby Food Using ICP-MS</strong></h3><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/labrulez-bucket-strapi-h3hsga3/an_01_01039_en_c563bb1b82.pdf"><strong>Full PDF for download</strong></a></li></ul><h4><strong>User Benefits</strong></h4><ul><li>Heavy metals in various baby foods can be analyzed simultaneously with sufficient sensitivity.</li><li>Stable analysis can be performed even for baby foods with high matrix content.</li><li>Using the standard LabSolutions ICPMS rinse function, the time to clean the sample introduction system is minimized, which prevents carryover.</li></ul><p>Infants’ metabolic pathways are still developing, and because of their lower body weight, they are known to be more susceptible to the effects of harmful substances. In the United States, the Baby Food Safety Act 2021<sup>1)</sup>, and in the EU, Commission Regulation (EU) 2023/915<sup>2)</sup> and Commission Regulation (EU) 2024/1987<sup>3)</sup> require the control of toxic metals contained in baby foods. ICP-MS is suitable for the analysis of trace amounts of toxic metal elements because it can perform multi-element simultaneous analysis with high sensitivity.</p><p>However, baby foods vary in matrix composition, which raises concerns about non-spectral interferences and long-term stability during ICP-MS analysis. This Application News describes the analysis of five baby foods with different matrices using the <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/library?mainauthorItems=1&amp;search=ICPMS-2040%2F2050"><strong>ICPMS-2040/2050</strong></a> (Fig. 1). Additionally, spike recovery tests and long-term stability were assessed based on the Food and Drug Administration (FDA) Elemental Analysis Manual (EAM) Section 4.7<sup>4)</sup>.</p><h4><strong>Equipment Configuration and Analysis Conditions&nbsp;</strong></h4><p>The equipment configuration is shown in Table 2. To reduce running costs, a mini-torch with lower argon gas consumption compared to conventional torches was used for analysis. Additionally, to streamline sample preparation, an Online Internal Standard Kit was utilized for online addition.&nbsp;</p><p>The analysis conditions are detailed in Table 3. After analyzing high-concentration samples, the sample introduction system can influence the analysis values of subsequent samples (carryover). If carryover occurs, re-measurement is necessary, which consumes additional time and samples. With LabSolutions ICPMS, rinse solutions can be set for each sample, enabling effective cleaning in minimal time. Normal cleaning was performed using pure water (Rinse solution 1), and an additional acid rinse solution (Rinse solution 2) was introduced only after high-concentration samples.</p><p>For example, Table 4 shows the difference in carryover concentration when measuring a blank sample after introducing a sample with a CCV concentration, comparing the case where rinse solution 2 is added for an additional 240 seconds to the case where it is not. Among the elements measured this time, Se and Hg tend to have a higher risk of carryover, but by introducing rinse solution 2, carryover was reduced to below the detection limit. Moreover, even if unexpectedly high-concentration samples are introduced, the Extended Rinsing function allows for automatic additional rinsing (Fig. 3). This eliminates the need to repeatedly check analysis values or to set a uniform cleaning time uniformly, thus reducing the verification effort, the amount of rinse solution required, and the analysis time while preventing carryover.&nbsp;</p><p>Furthermore, to minimize time spent cleaning the sample introduction system, ProActive Rinsing was used (Fig. 4). When measuring multiple samples, starting the rinse in advance during measurement reduces the measurement time for subsequentsamples.</p><h4><strong>Conclusion&nbsp;</strong></h4><p>In this Application News, elemental analysis of baby food was conducted using the ICPMS-2040/2050. We achieved detection limits that met stringent standards. The spike recovery tests yielded good results for all samples with different matrices, confirming the validity of the analysis. Additionally, we analyzed 50 samples of infant formula with a high matrix over approximately six hours and confirmed good stability. The ICPMS-2040/2050 offers high sensitivity, accurate analysis, and good stability. Its Extended Rinsing and ProActive Rinsing functions effectively clean the sample introduction system, preventing carryover. Therefore, the ICPMS-2040/2050 is a suitable instrument for elemental analysis in baby food.</p><h3><strong>4. Thermo Fisher Scientific: Food protection methods assessed by Surface Enhanced Raman Spectroscopy</strong></h3><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/labrulez-bucket-strapi-h3hsga3/food_protection_methods_surface_enhanced_raman_spectroscopy_an54670_en_5c5e701389.pdf"><strong>Full PDF for download</strong></a></li></ul><p>Lipid oxidation is a major issue for the meat industry as it can not only affect&nbsp;sensory quality in terms of flavor and odor but can also lead to the formation of toxic compounds such as malondialdehyde (MDA) and cholesterol oxidation products, as well as the accumulation of carbonyls, alcohols and volatile acids. The degree of oxidation depends on various factors such as the type of meat, the fat content, the storage temperature, the availability of oxygen and the type of packaging<sup>1, 2</sup>. To prevent oxidation, synthetic antioxidants are commonly added to meat products, but consumers are now demanding more natural products<sup>3</sup>. Several studies have been carried out to evaluate the antioxidant activity of many essential oils or extracts from plants or spices such as rosemary, cinnamon or oregano, and the new trend is to develop innovative packaging by adding these natural antioxidants directly to the packaging materials<sup>4–6</sup>. These materials, often films, are known as “active packaging” because they enable the controlled release of active agents either on the surface or in the internal atmosphere of the product, or by trapping the radicals responsible for harmful effects on food quality. However, the antioxidant performance of these films must be accurately determined to enable the selection of the right packaging for each foodstuff.&nbsp;</p><p>Among all the techniques available, Raman spectroscopy is a promising candidate for detecting most molecular species with high specificity and sensitivity, particularly in the presence of Surface-Enhanced Raman Scattering (SERS). Indeed, SERS is a physical phenomenon that occurs in the presence of a rough nano-structured metallic surface that causes the intensification of Raman signals from molecules adsorbed to the surface thanks to the combination of a chemical effect and an electromagnetic effect<sup>7</sup> . The metals used are generally gold or silver, which can be prepared by electrochemical roughening, metallic coating, or deposition of nanoparticles (often in a colloidal form). Commercial solutions are available, but many researchers prefer to create their own SERS substrates. The scope of this work is to investigate the potential of a home-made SERS substrate to compare the lipid oxidation over time in ground pork preserved either in a low-density polyethylene (LDPE) conventional packaging or in an active packaging containing oregano extract.</p><h4><strong>Material and method&nbsp;</strong></h4><p>Fresh ground pork meat was purchased in bulk from a local supermarket and 22 g samples of meat were placed in 5-cm diameter polystyrene Petri dishes. Each sample was covered with an active film and packed in an LDPE bag under a normal atmosphere. Reference samples were also prepared using conventional LDPE films. All samples were stored in a refrigerator at 5 °C and their lipid extracts were analyzed after 0, 7, 9, 11, 14 and 16 days using a home-made SERS substrate based on silver nanoparticles deposited on a glass Petri dish. A special home-made cooling system was used to perform the analyses at low temperature and SERS spectra were measured at -2 °C on a <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/products/2239"><strong>Thermo Scientific™ DXR3 Raman Microscope</strong></a> (Waltham, MA, USA) with a 532 nm laser source, a 900 lines/mm grating covering the 50-3500 cm-1 spectral range and an x10 objective (NA 0.40). The laser power was set at 5&nbsp;mW, and 20 exposures of 30 s each were selected to acquire all data. Thermo Scientific™ OMNIC™ v. 9.2 software was used for data collection and analysis. All the measurements were performed in triplicate. As the decrease in the peak at 1655&nbsp;cm-1 (stretching of C=C bonds from unsaturation) can be attributed to lipid peroxidation, and the 1439 cm-1 (scissoring deformation of CH<sub>2</sub>) is not affected by it, the area ratio between 1655 cm-1 and 1439 cm-1 bands was calculated to follow the lipid oxidation.</p><h4><strong>Conclusion&nbsp;</strong></h4><p>The effectiveness of a home-made SERS substrate coupled with a home-made cooling system was demonstrated for monitoring lipid oxidation in packaged ground pork meat over time. The advantages of this technique are its speed and the minimal sample handling requirements. An improvement factor of the order of 107 over conventional Raman was observed. This study also confirmed the greater efficacy of active packaging containing oregano extracts against lipid oxidation in ground pork, compared to conventional LDPE packaging.</p>

News from LabRulezICPMS Library - Week 09, 2026

<p><strong>This study investigates the impact of harvest time on the biofunctional properties of Schizonepeta tenuifolia, a medicinal plant widely used in herbal medicine. Key compounds, including rosmarinic acid, pulegone, and menthone, were quantified using HPLC and GC–MS, while antioxidant activity was assessed using DPPH, ABTS, and FRAP assays.</strong></p><p>Results showed that antioxidant capacity and phenolic content varied significantly with growth stage. Rosmarinic acid peaked at stage S5 and strongly correlated with antioxidant activity, while pulegone and menthone reached maximum levels at earlier and later stages, respectively. The optimal harvest periods were identified at stages S4 and S5, maximizing antioxidant potential and overall product quality.</p><blockquote><h4><strong>The original article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c08375"><strong>Effect of Harvest Time on the Biofunctional Properties of Schizonepeta tenuifolia Briq</strong></a></h4><p>Yong-Nam Cho, Yun-Sook Kim, Yeong-Bin Kim, Sang-Eun Lee, Min-Ji Gang, Se-Hee Jeon, Jae-Young Heo, and Sung-Tae Lee*</p><p>ACS Omega 2025, 10, 49, 60579–60584</p><p><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1021/acsomega.5c08375">https://doi.org/10.1021/acsomega.5c08375</a></p><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/"><strong>CC-BY 4.0</strong></a></h6></blockquote><p><strong>Selected sections from the article follow. Formats and hyperlinks were adapted from the original.</strong></p><div><p><i>S. tenuifolia</i> is a perennial plant from the Lamiaceae family, commonly used for both edible and medicinal purposes across Asia. Reaching a height of 60–150 cm, <i>S. tenuifolia</i> is a perennial plant characterized by a strong, woody stem and multiple branches. Its base is slightly quadrangular, appearing superficially as an obtuse quadrilateral with shallow grooves and a light covering of short hair.</p><p>The dried aerial parts of <i>S. tenuifolia</i> are used in herbal medicine to treat various skin diseases. <a href="javascript:void(0);">(1,2)</a> They also exhibit anti-inflammatory, antipruritic, insecticidal, and antiviral properties. <a href="javascript:void(0);">(3)</a> The main chemical components of <i>S. tenuifolia</i> are volatile oils, such as monoterpenoids (including pulegone, limonene, and menthone) <a href="javascript:void(0);">(4)</a> and compounds (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c08375#fig1">Figure 1</a>), such as phenolic compounds and glycosides. Pulegone, which is used in aromatherapy for flavoring and perfume, is a natural monoterpene obtained from the volatile oils of various plants. <a href="javascript:void(0);">(4)</a> However, reports suggest that it is a potent hepatotoxin whose metabolism generates p-cresol. <a href="javascript:void(0);">(5)</a> The mint-flavored natural monoterpene menthone has been widely used as a flavoring agent or perfume in the cosmetic, drug, and food industries. It is also used as a cooling agent, counterirritant for pain relief, and antidepressant-like substance. <a href="javascript:void(0);">(6)</a></p><p>All plants produce a variety of secondary metabolites to adapt to their environment. One of the most important groups of these metabolites are phenolic compounds, which are characterized by one or more aromatic rings (C6) containing one or more hydroxyl groups. <a href="javascript:void(0);">(7)</a> They play a role in various functions including plant growth, development, and defense. Phenols act as precursors to other important bioactive compounds commonly used in the pharmaceutical, cosmetic, and food industries. <a href="javascript:void(0);">(8)</a></p><p>Current trends in the food industry favor natural biofunctional compounds due to the increased demand and interest in health food. Therefore, <i>S. tenuifolia</i> is an excellent candidate. Traditionally, <i>S. tenuifolia</i> has been used as an ingredient in oriental medicine as well as in tea and soups. However, they contain volatile oils and are greatly affected by climate, cultivation conditions, and harvesting time. The objective of this study was to compare the biofunctional properties of <i>S. tenuifolia</i>, such as antioxidant activities, total phenolic content, and individual phenolic compounds at different harvest times to optimize its production in the food industry.</p><h4><strong>Materials and Methods</strong></h4><h5><strong>HPLC Analysis of Rosmarinic Acid and Luteolin</strong></h5><p>HPLC analysis was performed using a system from SHIMADZU Corporation (Japan) with a UV–VIS detector (SPD-20A), a pump (LC-20AD), a column oven (CTO-20A), and <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=1&amp;search=LCsolution+software"><strong>LCsolution software</strong></a>. The contents of rosmarinic acid (RA) and luteolin (LU) in the <i>S. tenuifolia</i> extract were quantified based on the method of Wang et al., <a href="javascript:void(0);">(12)</a> with slight modifications. The mobile phase consisted of water with 0.1% acetic acid (solvent A) and methanol (solvent B). Solvent B was changed as follows: 0 min, 80% B; 10 min, 40% B; 15 min, 20% B; 25 min, 10% B; and 25–40 min, 80% B. The total running time was 40 min, with a flow rate of 0.5 mL/min. A YMC-Pack Pro C18 RS column (250 × 4.6 mm, 5.0 μm particle size) was used at 30 °C. Before injection, the extracts were filtered using a 0.45-μm syringe filter (Advantec), and the absorbance was measured at 330 nm. RA and LU were identified by their respective peaks and retention times with reference to standard compounds. Calibration curves were prepared using RA (<i>y</i> = 3.970148e-005<i>x</i> + 10.26398, <i>R</i><sup>2</sup> = 0.9992) and LU (<i>y</i> = 3.339664e-005<i>x</i> + 3.114092, <i>R</i><sup>2</sup> = 0.9999) standards, and the phenolic compounds in the extracts were expressed as mg/g DW.</p><h5><strong>Gas Chromatography–Mass Spectrometry (GC–MS) Analysis</strong></h5><p>A 1 g sample of <i>S. tenuifolia</i> was placed in a 50 mL conical tube, and 20 mL of chloroform was added. The sample was soaked at room temperature for 2 h. After centrifugation, 1 mL of the extract was filtered through a 0.2-μm syringe filter and used for the analysis. GC–MS analysis was performed using an <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=7890A"><strong>Agilent 7890A gas chromatograph</strong></a> (Agilent Technologies, USA) with a <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=5975C"><strong>5975C mass selective detector</strong></a> and autosampler (split ratio: 50:1), controlled by Agilent Chemstation software. The analysis was conducted on a DB-5MS column (30 × 250 μm × 0.25 μm film) with helium as the carrier gas at 1 mL/min. The temperature program was as follows: hold at 50 °C for 4 min, increase to 220 °C at 4 °C/min with a 2 min hold, and then increase to 280 °C at 20 °C/min with a 15 min hold. The injection temperature was 250 °C, with the transfer line at 280 °C and the ion source at 230 °C. The mass spectrometer was operated in electron impact mode at 70 eV with selected ion monitoring (SIM). Pulegone and menthone were used as standards (<i>y</i> = 1069.8<i>x</i> – 6596.1, <i>R</i><sup>2</sup> = 0.9991) and expressed as mg/kg.</p><h4><strong>Results and Discussion</strong></h4><h5><strong>GC–MS Analysis</strong></h5><p>The two compounds identified using the SIM mode are presented in <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c08375#tbl4">Table 4</a>. In this study, the two major components, pulegone and menthone, were found to constitute 65.6 and 4.35% of the total peak area, respectively. <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c08375#fig4">Figure 4</a> illustrates the bioactive constituents identified in <i>S. tenuifolia</i>. The pulegone content increased from the growing stage (S1) to the spike formation stage (S3) and decreased from the full bloom stage (S4) to the fruiting stage (S6), with the maximum value of 8.55 ± 0.55 mg/g observed at S3. Conversely, the menthone content consistently increased from the growing stage (S1) to the fruiting stage (S6), reaching 1.15 ± 0.43 mg/g at the fruiting stage (S6), with a particularly sharp increase observed from the fruiting formation stage (S5) to the fruiting stage (S6). Overall, the results suggest that the optimal harvest time for <i>S. tenuifolia</i>, based on the content of its major target compound, pulegone, is from the spike formation stage (S2–S3), during which the pulegone content was 1.7–3.0 times higher than at other stages. However, previous studies indicated that the optimal harvesting time for <i>S. tenuifolia</i> was at the spike formation stage. Although the content of pulegone showed a slight increasing trend during harvesting times, the menthone content tended to decrease over the same period. <a href="javascript:void(0);">(4)</a> Notably, the quality of <i>S. tenuifolia</i> may have been influenced by variations in the cultivars and growing conditions. Several studies have shown that different cultivars and growing conditions significantly affect crop performance. <a href="javascript:void(0);">(20,21)</a></p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/ACS_Omega_2025_10_49_60579_60584_Figure_4_GC_MS_analysis_of_pulegone_and_menthone_contents_in_S_tenuifolia_extracts_ce02766b46.jpeg" alt="ACS Omega 2025, 10, 49, 60579–60584: Figure 4. GC–MS analysis of pulegone and menthone contents in S. tenuifolia extracts." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_ACS_Omega_2025_10_49_60579_60584_Figure_4_GC_MS_analysis_of_pulegone_and_menthone_contents_in_S_tenuifolia_extracts_ce02766b46.jpeg 245w," sizes="100vw" width="2000" height="889"></p><h4><strong>Conclusions</strong></h4><p>This study demonstrates that the functional properties of <i>S. tenuifolia</i>, such as antioxidant activity and phenolic content, are significantly influenced by the harvesting time. Previous studies on <i>S. tenuifolia</i> or related Lamiaceae species have mainly focused on evaluating the antioxidant activity of crude extracts or quantifying a limited number of compounds at a single harvest stage. In contrast, our work systematically compared multiple functional parameters across five distinct growth stages, integrating changes in phenolic compounds (especially, rosmarinic acid), volatile monoterpenes (pulegone and menthone), and antioxidant activities. The best harvesting time for ABTS, FRAP, and TPC was S4, compared to other stages, and for DPPH it was S6. The contents of RA and LU in <i>S. tenuifolia</i> extracts showed the highest content of RA at S5. RA was strongly correlated with DPPH radical scavenging (<i>R</i><sup>2</sup> = 0.877–0.904), ABTS radical scavenging (<i>R</i><sup>2</sup> = 0.890–0.907), and FRAP (<i>R</i><sup>2</sup> = 0.964–0.980). The optimal harvesting times for pulegone and menthone are likely during S3 to S4, with menthone undergoing an approximately 15-fold increase from S3 to S4. Overall, the results suggest that the optimal harvesting time for maximizing these functional properties, while also maintaining high levels of pulegone and menthone, is during S4 and S5, with a marked increase in the antioxidant activity and phenolic content. By identifying the best harvesting window, producers can enhance the quality and health benefits of <i>S. tenuifolia</i>-based products, improving their effectiveness in foods, herbal remedies, and dietary supplements.</p></div>

Effect of Harvest Time on the Biofunctional Properties of Schizonepeta tenuifolia Briq

Determination of Copolymer Block-Length Distributions Using Fragmentation Data Obtained from Tandem Mass Spectrometry

<p><strong>This study introduces a forensic laboratory module designed to quantify environmental tobacco smoke (ETS) exposure in human hair. Using controlled smoke exposure and analysis by UV–Vis spectroscopy, FTIR spectroscopy, and zeta potential measurements, students investigated how untreated, dyed, and bleached hair differ in their capacity to adsorb ETS residues.</strong></p><p>Implemented over three weeks, the module included pre- and postlab assessments to evaluate learning outcomes. Results showed measurable improvements in student understanding, technical skills, and application of forensic analytical techniques. The experiment provides a practical teaching tool for forensic chemistry while demonstrating how chemical treatments influence hair’s interaction with environmental contaminants.</p><blockquote><h4><strong>The original article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.jchemed.5c00479"><strong>Developing and Demonstrating a Lab Method for Quantifying Hair Exposure to Environmental Tobacco Smoke with a Forensic Perspective</strong></a></h4><p>Tanique Z. Jones, Christopher J. Trejo, Somayeh Mohammadi, and Hamidreza Sharifan*</p><p>J. Chem. Educ. 2026, 103, 1, 479–487</p><p><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1021/acs.jchemed.5c00479">https://doi.org/10.1021/acs.jchemed.5c00479</a></p><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/"><strong>CC-BY 4.0</strong></a></h6></blockquote><p><strong>Selected sections from the article follow. Formats and hyperlinks were adapted from the original.</strong></p><div><p>In forensic chemistry education, a reliable noninvasive lab module to assess cannabis and environmental tobacco smoke (ETS) exposure is critical as many crime scenes are associated with smoke and drug consumption. <a href="javascript:void(0);">(1,2)</a> Traditional lab methods, such as blood and urine analysis, are costly, often unfeasible in many institutes and require lengthy ethical approval processes, moreover, they provide only a snapshot of recent exposure and may not reflect long-term accumulation. <a href="javascript:void(0);">(3,4)</a> Hair analysis, on the other hand, can provide a comprehensive overview of an individual’s exposure over weeks to months, making it an invaluable tool in forensic chemistry education. <a href="javascript:void(0);">(5−7)</a> This study aims to develop a robust lab module that enables students to effectively understand hair exposure to ETS, with a specific focus on the differential retention of smoke residues in untreated, dyed, and bleached hair. We developed an experimental setup that can be further commercialized and utilized in educational settings for forensic and environmental studies. Through teaching forensic chemistry over four years, the lead author identified the need of a lab module in forensic chemistry education to be affordable, reliable, and noninvasive for students to assess environmental exposures that play a role in legal and investigative contexts. <a href="javascript:void(0);">(8,9)</a></p><p>ETS, commonly referred to as secondhand smoke, poses significant health risks and remains a pervasive issue in public health. <a href="javascript:void(0);">(10−12)</a> The detrimental effects of ETS exposure, including respiratory illnesses, cardiovascular diseases, and various cancers, are well-documented. <a href="javascript:void(0);">(13)</a> However, accurately quantifying an individual’s exposure to ETS, particularly in forensic contexts, presents unique challenges. Previous research highlights that ETS residues, specifically nicotine and its metabolites, serve as significant forensic markers in cases involving exposure assessments or custody disputes due to their persistence and detectability in biological matrices such as hair. <a href="javascript:void(0);">(14,15)</a> Hair, as a biological matrix, offers a distinctive advantage for assessing long-term exposure to environmental pollutants, <a href="javascript:void(0);">(16)</a> including tobacco smoke, narcotics, and marijuana. <a href="javascript:void(0);">(17)</a> This is due to its ability to incorporate and retain various substances over extended periods, providing a historical record of exposure. <a href="javascript:void(0);">(18,19)</a> Unlike blood or urine, which reflect recent exposure, hair analysis provides a longer window of detection, making it possible to assess chronic exposure to ETS. <a href="javascript:void(0);">(20)</a> In addition, using the hair supply for the forensic teaching lab is low-risk and cost-effective. Further, this technique is particularly useful in cases where long-term exposure needs to be demonstrated. Hair collection is a noninvasive procedure, easily performed without causing discomfort or distress to individuals. <a href="javascript:void(0);">(21,22)</a> This is especially advantageous in forensic contexts where minimal invasiveness is preferred. Hair has the unique ability to incorporate and retain nicotine and other smoke residues over time. <a href="javascript:void(0);">(23,24)</a> By examining untreated, dyed, and bleached hair, this lab module can empower students to differentiate hair treatments role in the adsorption of ETS components, enhancing the accuracy of exposure assessments. <a href="javascript:void(0);">(25,26)</a> This Lab module is flexible and integrable to improve understanding of the impact of cosmetic treatments on the absorption of environmental toxins. Through this experiment, instructors can design various forensic scenarios, including criminal investigations, workplace exposure assessments, and custody disputes where ETS exposure might be a relevant factor. <a href="javascript:void(0);">(27)</a> It provides forensic experts with a robust tool to support their findings with scientifically validated data. <a href="javascript:void(0);">(28)</a> This innovative approach enhances the forensic toolkit, allowing for more accurate and comprehensive exposure assessments.</p><h4><strong>Experimental</strong></h4><h5><strong>UV–Visible Spectroscopy Analysis</strong></h5><p>The concentration of smoke residues in the hair samples was quantified using UV–visible (UV–vis) spectroscopy (PerkinElmer) after extracting the adsorbed residues by rinsing the exposed hair samples with methanol three times. The resulting methanol extracts were scanned using a full wavelength range of 200–700 nm. Among the observed spectra, the absorbance at 280 nm was specifically monitored using second-order derivative processing.</p><p>The selection of 280 nm was based on its established association with strong π–π* transitions of aromatic compounds such as nicotine and polyaromatic hydrocarbons, which are prominent components of tobacco smoke. This wavelength consistently showed peak absorbance in our extracts across different hair types and exposure conditions, making it a reliable indicator for quantifying smoke residue deposition.</p><p>To ensure measurement accuracy, a baseline scan using deionized water was performed prior to sample analysis to subtract background noise. Spectra were collected at room temperature using a 2.5 nm sampling interval, fast scan speed, and 5.0 nm slit width. The UV–vis absorbance data at 280 nm were used to evaluate the extent of smoke residue adsorption on virgin, dyed, and bleached hair. Comparative analysis of these spectra provided insight into how cosmetic treatments influence the hair’s capacity to retain environmental smoke contaminants.</p><h5><strong>Zeta Potential Measurement</strong></h5><p>Hair samples were then cut into small pieces (&lt;1 cm in length) using scissors to facilitate grinding. The cut hair pieces were placed into a mortar and a small amount of liquid nitrogen was added to freeze the hair, making it brittle and easier to grind. The pestle was used to grind the frozen hair into a fine powder until a uniform consistency was obtained. 0.1 g of the hair powder was weighed using an analytical balance and transferred to a clean 15 mL polypropylene tube. To prepare the suspension, we added 10 mL of deionized (DI) water to the tube containing the hair powder and sonicated the suspension for 10 min to ensure uniform dispersion. The suspension was then centrifuged at 3000 rpm for 5 min to remove any large aggregates, and the supernatant was collected for zeta potential measurement. The hair suspension supernatant was transferred to the sample cell of the analyzer. Zeta potential measurements (n = 3) were performed using Malvern Zetasizer (Malvern, UK). The data was analyzed to determine the average zeta potential of the hair powder suspension, and the values for untreated hair were compared with those for dyed and bleached hair.</p><h5><strong>FTIR Analysis</strong></h5><p>The changes in functional groups of hair samples before and after smoke exposure were evaluated using FTIR at room temperature. The FTIR analysis adhered to the ASTM E1252 standard procedure, <a href="javascript:void(0);">(29)</a> employing the <a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/library?mainauthorItems=3&amp;search=Nicolet+iS5"><strong>Thermo Scientific Nicolet iS5 FT-IR Spectrometer</strong></a>. <a href="javascript:void(0);">(30)</a> During the linear scan mode, the sampling depth varied across the spectrum. With an optical velocity of 0.47 cm/s, the Fourier frequency ranged from 470 to 940 Hz, covering a spectral range of 400 to 3000 cm<sup>–1</sup>.</p><h4><strong>Results and Discussion</strong></h4><p>As shown in <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.jchemed.5c00479#fig2">Figure 2</a>, the absorbance values recorded at the wavelength of 280 nm indicated potential absorption of nicotine and tar components with a positive correlation to the time of exposure within a 60 min interval. Hair treated with permanent dye displayed the highest levels of smoke residue deposition across all exposure intervals. The UV–visible absorbance spectra revealed a significant increase in smoke residue absorption compared to virgin and bleached hair, by 1.8 and 3.2 times higher at 60 min, respectively.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/J_Chem_Educ_2026_103_1_479_487_Figure_2_Absorbance_of_smoke_residues_dissolved_in_methanol_from_different_hair_types_over_time_fc288f5fce.jpeg" alt="J. Chem. Educ. 2026, 103, 1, 479–487: Figure 2. Absorbance of smoke residues dissolved in methanol from different hair types over time. The graph shows the absorbance 280 nm corresponding to nicotine and tar components on hair within 15, 30, 45, and 60 min." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_J_Chem_Educ_2026_103_1_479_487_Figure_2_Absorbance_of_smoke_residues_dissolved_in_methanol_from_different_hair_types_over_time_fc288f5fce.jpeg 181w," sizes="100vw" width="934" height="807"></p><p><a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.jchemed.5c00479#fig3">Figure 3</a> shows the impact of cigarette smoke on untreated, dyed, and bleached hair samples using FTIR spectroscopy. This technique allowed students to investigate molecular-level changes in hair composition after exposure to ETS, providing a hands-on opportunity to connect theory with application. <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.jchemed.5c00479#fig3">Figure 3</a>A presents FTIR spectra of untreated hair (black line) and smoke-exposed untreated hair (red line). After exposure, noticeable new peaks and shifts in transmittance intensities emerge, indicating chemical alterations. Changes were especially prominent in the 3000–2800 cm<sup>–1</sup> region (C–H stretching of alkanes) and the 1700–1500 cm<sup>–1</sup> range (Amide I and II bands), which reflect modifications to the protein backbone of hair. These spectral changes served as real-time evidence of environmental interaction with biological samples. <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.jchemed.5c00479#fig3">Figure 3</a>B shows similar comparisons for dyed hair, where exposure to smoke caused intensified shifts in the 3500–3200 cm<sup>–1</sup> region (O–H and N–H stretching vibrations) and 1600–1500 cm<sup>–1</sup> (Amide II region). These alterations suggest chemical interactions between dye constituents and smoke residues. The elevated response in dyed hair indicates a higher reactivity due to prior chemical treatment.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/J_Chem_Educ_2026_103_1_479_487_Figure_3_FTIR_spectra_of_hair_samples_exposed_to_cigarette_smoke_6284805abf.jpeg" alt="J. Chem. Educ. 2026, 103, 1, 479–487: Figure 3. FTIR spectra of hair samples exposed to cigarette smoke. (A) Untreated hair compared to untreated hair exposed to cigarette smoke. (B) Dyed hair compared to dyed hair exposed to cigarette smoke. (C) Bleached hair compared to bleached hair exposed to cigarette smoke." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_J_Chem_Educ_2026_103_1_479_487_Figure_3_FTIR_spectra_of_hair_samples_exposed_to_cigarette_smoke_6284805abf.jpeg 245w," sizes="100vw" width="2100" height="580"></p><p><a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acs.jchemed.5c00479#fig3">Figure 3</a>C compares bleached hair before and after smoke exposure, with changes spanning 500–3200 cm<sup>–1</sup>. The broadening of peaks in the O–H stretching region and changes in Amide I and II bands point to structural degradation and protein damage induced by the dual effects of bleaching and smoke exposure. The increased porosity of bleached hair likely enhances its susceptibility to smoke residue adsorption. From an educational standpoint, this FTIR module reinforced critical analytical thinking by guiding students through spectral interpretation of real biological samples. Rather than working with abstract compounds, students explored how cosmetic alterations change a material’s chemical behavior and how forensic tools like FTIR can detect those changes. By comparing spectra across different hair conditions, students practiced identifying functional groups and recognizing patterns in complex data sets, skills directly transferrable to forensic, biomedical, and environmental chemistry fields.</p><p>Furthermore, this hands-on experience emphasized the interdisciplinary nature of forensic chemistry, combining biology, toxicology, and analytical instrumentation. Students gained confidence in interpreting real-world data and understanding how molecular-level changes relate to broader questions about environmental exposure and personal history, key themes in modern forensic investigations. This lab taught FTIR instrumentation also illustrated its power in addressing societal and legal questions through science.</p><h4><strong>Conclusion</strong></h4><p>This work delivers a practical, noninvasive laboratory module that quantifies hair exposure to environmental tobacco smoke while building core forensic-analytical competencies. Using controlled smoke exposure coupled with UV–visible spectroscopy, FTIR, and zeta potential measurements, students were able to detect and interpret chemical signatures of ETS on untreated, dyed, and bleached hair. Across techniques, cosmetic treatment was a decisive factor: treated hair exhibited distinct surface chemistry and structural changes that altered residue interactions and detectability. In our pilot, dyed hair frequently showed higher methanol-extractable residues by UV–Vis, whereas bleaching produced marked shifts in functional groups and more negative surface charge, indicating treatment-dependent mechanisms of adsorption and retention. These complementary observations reinforce the evidentiary value of multimodal analysis in exposure assessment and demonstrate how matrix history (cosmetic treatment) must be considered in forensic interpretation.</p><p>Pedagogically, the module achieved measurable learning gains. Pre/post assessments showed increased familiarity with forensic hair analysis, improved confidence with instrumental methods, and stronger capacity to translate spectra and surface-charge data into defensible conclusions. Because the workflow uses accessible instrumentation, clearly defined safety practices, and inexpensive materials, it is readily scalable for undergraduate teaching laboratories and adaptable to varied forensic scenarios (e.g., custody disputes, workplace exposure, scene reconstruction). Future iterations should incorporate quantitative calibration for specific ETS markers (e.g., nicotine/cotinine), broaden donor hair diversity and treatment histories, examine repeated/longer exposures and alternative smokes (e.g., cannabis), and evaluate decontamination protocols. Method validation across cohorts and institutions, coupled with structured interpretation frameworks, will further strengthen reliability and courtroom utility. Overall, the module integrates authentic forensic inquiry with robust analytics, providing a transferable teaching and investigative tool for assessing individual ETS exposure in hair.</p></div>

Developing and Demonstrating a Lab Method for Quantifying Hair Exposure to Environmental Tobacco Smoke with a Forensic Perspective

<p><strong>In the week of March 2, the following webinars await you in the field of gas / solid phase and especially Raman, FTIR, GC and GC/MS.</strong></p><blockquote><h4><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinars"><strong>👉 DETAILS AND REGISTRATION IN THE WEBINARS SECTION</strong></a></h4><p><strong>👉 Search and filter in the largest global database</strong> with over <strong>5 500 GC, LC, MS and spectroscopy webinars</strong>.</p></blockquote><div><div><div><div><div><div><h5><strong>1. SelectScience: Cracking the Toughest Food Matrices with Advanced GC Column Technology</strong></h5><ul><li>We, 4.3.2026 17:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinar/5914">Registration</a></li></ul><p>Discover how next-generation GC column technology helps overcome multi-pesticide challenges by improving robustness, sensitivity, throughput, and column lifetime in complex food matrices.</p><h5><strong>2. Agilent Technologies: Mud Logging and Natural Gas Solutions for Micro-GC</strong></h5><ul><li>Th, 5.3.2026 10:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinar/5985">Registration</a></li></ul><p>This session provides an overview of Micro-GC–based solutions for different segments of natural gas analysis, including mud logging applications.</p></div></div></div></div></div></div>

Webinars LabRulezGCMS Week 10/2026

<p><strong>In the week of March 2, the following webinars await you in the field of liquid phase and especially HPLC and LC/MS.</strong></p><blockquote><h4><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinars"><strong>👉 DETAILS AND REGISTRATION IN THE WEBINARS SECTION</strong></a></h4><p><strong>👉 Search and filter in the largest global database</strong> with over <strong>5 500 GC, LC, MS and spectroscopy webinars</strong>.</p></blockquote><h5><strong>1. Thermo Fisher Scientific: Vanquish High-Throughput LC Systems</strong></h5><ul><li>Tu, 3.3.2026 11:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5948">Registration</a></li></ul><p>Discover how Thermo Scientific Vanquish high-throughput LC systems increase HPLC, UHPLC, and LC-MS productivity through Duo and Tandem configurations, parallelization, and smarter automation.</p><h5><strong>2. Thermo Fisher Scientific: SureQuant Hybrid DIA</strong></h5><ul><li>Tu, 3.3.2026 14:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/6004">Registration</a></li></ul><p>Join this free workshop on SureQuant hybrid DIA using Orbitrap Astral and Proteome Discoverer to learn targeted peptide quantification with isotopic standards.</p><h5><strong>3. Phenomenex: Small Scale, Big Impact – Scaling Micro/Nano LC</strong></h5><ul><li>We, 4.3.2026 11:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5963">Registration</a></li></ul><p>Explore the benefits of LC miniaturization and learn how combining core-shell technology with micro and nano flow enhances efficiency, sensitivity, and selectivity.</p><h5><strong>4. Technology Networks: Addressing Common Misconceptions in Residual Host Cell DNA Testing</strong></h5><ul><li>We, 4.3.2026 17:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5913">Registration</a></li></ul><p>Learn how to design robust residual host cell DNA testing workflows for biotherapeutic QC, meeting regulatory expectations and enabling accurate ultra-low-level quantitation.</p><h5><strong>5. Thermo Fisher Scientific: ProteinTurnoverAtlas™ – A Resource for Modern Drug Discovery</strong></h5><ul><li>Th, 5.3.2026 15:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5987">Registration</a></li></ul><p>Discover how ProteinTurnoverAtlas™ and MouseTurnoverAtlas™ leverage pulsed SILAC and LC-MS/MS to map protein half-lives and guide target selection and dosing strategies.</p><h5><strong>6. Waters Corporation: From Raw Materials to Conjugation Sites – Advanced LC, MS and MALS Strategies for AOC Characterization and Monitoring</strong></h5><ul><li>Th, 5.3.2026 17:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5916">Registration</a></li></ul><p>Explore comprehensive characterization of Antibody Oligonucleotide Conjugates (AOCs) using advanced LC-MS and LC-MALS analytical strategies.</p><h5><strong>7. SCIEX: Biopharma Fundamentals – LCMS Biopharma Characterization</strong></h5><ul><li>Fr, 6.3.2026 11:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/webinar/5960">Registration</a></li></ul><p>Join this masterclass to learn practical LC-MS strategies for protein identity, purity, sequence, and PTM characterization in biopharmaceutical workflows.</p>

Webinars LabRulezLCMS Week 10/2026

<p><strong>In the week from March 2, the following webinars await you in the field of atomic and molecular spectroscopy and spectrometry</strong></p><blockquote><h4><a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/webinars"><strong>👉 DETAILS AND REGISTRATION IN THE WEBINARS SECTION</strong></a></h4><p><strong>👉 Search and filter in the largest global database</strong> with over <strong>5 500 GC, LC, MS and spectroscopy webinars</strong>.</p></blockquote><h5><strong>1. Bruker: Ride the Tide – Novel NMR Approaches for Peptide Conformation and Kinetics Characterization</strong></h5><ul><li>Tu, 3.3.2026 17:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/webinar/5842">Registration</a></li></ul><p>Discover advanced NMR workflows for cyclic peptides and macrocycles, combining minimal restraints, high-resolution 3D conformations, and flow-NMR for real-time kinetic analysis.</p><h5><strong>2. Anton Paar: Heated Stories – What Differential Scanning Calorimetry Reveals About Petrochemical Materials</strong></h5><ul><li>Th, 5.3.2026 16:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/webinar/5843">Registration</a></li></ul><p>Learn how Differential Scanning Calorimetry (DSC) reveals oxidation, thermal stability, and phase behavior in lubricants, fuels, and bituminous materials under thermal stress.</p><h5><strong>3. SPECTRO Analytical Instruments: Boost Your ICP-OES Accuracy</strong></h5><ul><li>Th, 5.3.2026 17:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://icpms.labrulez.com/webinar/5798">Registration</a></li></ul><p>Explore how advanced ICP-OES solutions simplify complex analytical workflows and deliver accurate, dependable results across diverse applications.</p>

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