New strategies for non-targeted quantification in comprehensive two-dimensional gas chromatography: The potential of reconstructed TIC response factor surfaces

<p><strong>Our Library never stops expanding. What are the most recent contributions to LabRulezGCMS Library in the week of 18th August 2025? Check out new documents from the field of the gas phase, especially GC and GC/MS techniques!</strong></p><blockquote><p><span style="font-size:20px;">👉 </span><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library"><span style="font-size:20px;"><strong>SEARCH THE LARGEST REPOSITORY OF DOCUMENTS ABOUT GCMS AND 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://icpms.labrulez.com/library"><strong>LabRulezICPMS</strong></a> libraries.</p></blockquote><p>This week we bring you poster by <strong>Agilent Technologies / ASMS </strong>and application note<strong> </strong>by<strong> Shimadzu!</strong></p><h3><strong>1. Agilent Technologies / ASMS: New Pollutant Screening of Environmental Samples Using High-Resolution GC/Q-TOF and Accurate Mass Spectral Library of Emerging Environmental Pollutants&nbsp;</strong></h3><ul><li>Poster</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/ps_7250_pdcl_library_pal3_suremass_asms_2025_thp_083_en_agilent_3f1ac53d50.pdf"><strong>Full PDF for download</strong></a></li></ul><p>This paper conducts qualitative and semi - quantitative analysis of complex GC/Q-TOF sample data by using high-resolution, accurate-mass gas chromatography/quadrupole time-of-flight mass spectrometry (GC/Q-TOF), an accurate mass spectral library of environmental pollutants specifically created for emerging pollutant screening, and analytical software with a screening process platform. Actual environmental water samples are used to verify the sensitivity, accuracy, and spiked recovery rate of the solution. All results confirm that this solution is simple, stable, and effective, providing technical support for emerging pollutant screening.</p><h4><strong>Experimental</strong></h4><h5><strong>Instrument Analysis&nbsp;</strong></h5><p>The samples were analyzed by <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=8890+GC"><strong>Agilent 8890 GC</strong></a> and <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=7250+GC%2FQ-TOF"><strong>7250 high resolution accurate mass GC/Q-TOF system</strong></a>, It was configurated with a mid-column backflush setup (Figure 1). A 55.5 - min retention time locked GC oven temperature program is utilized which is listed in Table 1. The key mass spectrometry parameters of the GC/Q-TOF are as follows: It operates in the Electron Ionization (EI) mode with an energy of 70 electron volts, conducts detection in the time-of-flight scan mode within a mass-to-charge ratio range of 50 - 1000. The spectral acquisition rate is 5 Hz, and both the interface temperature and the source temperature are set at 280 °C. Data analysis is performed with the assistance of MassHunter data analysis software. The high-resolution accurate mass spectral library employed in the screening process is independently created by the laboratory.</p><h5><strong>Data Analysis&nbsp;</strong></h5><ul><li>The data processing used Agilent <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=Masshunter+software"><strong>Masshunter data analysis software</strong></a>, including Suremass.&nbsp;</li><li>The target screening of new pollutants was based on an independently created by the laboratory GC/Q-TOF PCDL library<sup>1</sup>.</li></ul><h4><strong>Conclusions&nbsp;</strong></h4><ul><li>Based on the currently collected list of new pollutants, a truly meaningful new pollutant PCDL high-resolution spectral library has been created.&nbsp;</li><li>This work demonstrated a total workflow for targeted screening and semi-quantification in real water sample.&nbsp;</li><li>The confidence in identification of new pollutants was enhanced by stable RT and excellent mass accuracy as a result of using an RTL backflush method and highresolution accurate mass measurement.</li></ul><h3><strong>2. Shimadzu: Analysis of SAF Using Comprehensive Two- Dimensional Gas Chromatography (GC× GC)&nbsp;</strong></h3><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/an_01_00862_en_f1ee0a435f.pdf"><strong>Full PDF for download</strong></a></li></ul><h4><strong>User Benefits</strong></h4><ul><li>By comparing chromatograms obtained as two-dimensional images, it can be utilized for quality control Inspection of SAF.</li><li>Changing the column combination customizes separation characteristics to the sample composition.</li><li>Utilizing the FASST (Fast Automated Scan/SIM Type) allows for the simultaneous analysis of the composition of SAF and the quantitative analysis of antioxidants.</li></ul><p>SAF (Sustainable Aviation Fuel) produced from waste cooking oil, used paper, and sugarcane has gained attention in recent years from the perspective of achieving a carbon neutral society. The physical properties of SAF,such as combustibility, vary depending on its components. Therefore, component analysis of SAF is crucial; however, since SAF is a mixture of various hydrocarbons, complete separation of each component is extremely challenging. Comprehensive two-dimensional gas chromatography (GC×GC), which utilizes the separation characteristics of two different types of columns, is an effective method for analyzing SAF with such a complex composition. Additionally, the GCMS-QP2050 enables ultra-fast scanning (30,000 u/sec), which improves the separation of adjacent peaks and allows for high-precision qualitative analysis(Application News No.01-00788-EN).</p><p>In this application, two types of SAF (A and B) and one intermediate product from the SAF production process (C) were measured using a combination of GC×GC with a non-polar column as the first column and a medium-polarity column as the second column. The two-dimensional images allow for a visual representation of the composition distribution, making quality control Inspection. Moreover, high separation of paraffins and naphthenes using a combination of a medium-polar column as the first column and a non-polar column asthe second column, as well as the quantification of antioxidants in SAF, which are regulated by concentration in ASTM D2425 will be introduced.</p><h5><strong>System Configuration</strong></h5><ul><li><strong>GC Model</strong>: <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=1&amp;search=Nexis%E2%84%A2+GC-2030"><strong>Nexis GC-2030</strong></a> / <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=1&amp;search=AOC-30i"><strong>AOC-30i</strong></a></li><li><strong>MS Model</strong>: <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=1&amp;search=GCMS-QP2050"><strong>GCMS-QP2050</strong></a> (TMP exhaust: 255 L/sec)</li><li><strong>Injection Port</strong>: SPL</li><li><strong>Modulator: </strong>ZX1 thermal modulator (ZOEX corp.)</li><li><strong>Nitrogen generator: </strong>MT-24F (System Instruments Co., Ltd.)</li><li><strong>Software</strong>:<ul><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=1&amp;search=Labsolutions+GCMS"><strong>Labsolutions<sup>TM</sup> GCMS</strong></a></li><li>GC Image (GC Image, LLC)</li></ul></li><li><strong>Library: </strong>NIST Mass Spectral Library</li></ul><h4><strong>Conclusion</strong></h4><p>Three SAF samples were measured using a combination of lowpolar to medium polar columns and compared the twodimensional images. The two-dimensional images allow for intuitive comprehension of the distribution of each component, making it easy to identify differences in composition and conducting quality control Inspection. Additionally, in the measurement of SAF using a combination of medium-polar to non-polar columns, the separation of paraffins and naphthenes was improved. Furthermore, by utilizing the FASST, composition analysis of SAF and quantitative analysis of antioxidants were simultaneously performed, which are regulated by concentration in ASTM D2425.</p>

News from LabRulezGCMS Library - Week 34, 2025

<p><strong>Our Library never stops expanding. What are the most recent contributions to LabRulezGCMS Library in the week of 15th September 2025? Check out new documents from the field of the gas phase, especially GC and GC/MS techniques!</strong></p><blockquote><p><span style="font-size:20px;">👉 </span><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library"><span style="font-size:20px;"><strong>SEARCH THE LARGEST REPOSITORY OF DOCUMENTS ABOUT GCMS AND 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://icpms.labrulez.com/library"><strong>LabRulezICPMS</strong></a> libraries.</p></blockquote><p>This week we bring you posters by <strong>Agilent Technologies / ASMS, Shimadzu / ASMS </strong>and application note by <strong>EST Analytical!</strong></p><h3><strong>1. Agilent Technologies / ASMS: Beyond Aligners: Unmasking Hidden Extractables and Leachables in Orthodontic Devices</strong></h3><ul><li>Poster</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/ps_7250_extractables_leachables_asms_2025_tp_318_en_ucsf_3e88cfbf5c.pdf"><strong>Full PDF for download</strong></a></li></ul><p>Increasingly popular in orthodontics, clear aligners promised to users’ improved comfort, compliance and flexibility. It also came with prolonged intraoral exposure. The literature on the potential for leaching components of the polymer used to manufacture the invisible aligners is sparse. Despite the benefits, user submitted cases in the FDA retrospective analysis report several adverse effect ranging from swelling, hives, itchiness and even difficulty breathing1 . Previous works examined the potential of leaching in retainers but used conditions far from the in-vivo setting2 . We used samples closest to user conditions and harnessed the power of Gas Chromatography High Resolution Mass Spectrometry (GC-HRMS) and the power of curated and annotated libraries to find candidate compounds that could be at the origin of the reported adverse effects. We also used multivariate statistics to establish relationships between the compounds and metadata.</p><h4><strong>Experimental</strong></h4><h5><strong>Sample Analysis&nbsp;</strong></h5><p>Samples were analyzed using the <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?manufacturerItems=1&amp;search=7250"><strong>Agilent 7250 accurate mass GC-qTOF</strong></a> equipped with the <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?manufacturerItems=1&amp;search=8890+GC"><strong>8890 GC</strong></a> and a DB-5MS UI column (30m x 0.25 x 0.25). The inlet temperature was 280°C and the transfer line temperature was 325°C. The oven program was as follows: 50°C for 1 min, ramp at 25°C to 170°C, hold for 1 min; then ramp at 15°C to 300°C, hold for 10 min; then ramp at 20 °C to 325°C and hold for 5 min. The solvent delay was 4 min. The data were acquired in electron ionization (EI) mode using mass range 45 to 1000 m/z. The source temperature was 230°C, and the emission current was 5 µA. A mix of alkanes was run along with the samples and blanks and an Extractables and Leachables (E&amp;L) standard mixture was run as a quality check.&nbsp;</p><h5><strong>Data Analysis&nbsp;</strong></h5><p>Retention indices were used in consolidating library matches in both the Agilent HRMS E&amp;L library and the NIST23 library. Data analysis was conducted on Unknown Analysis software from Agilent that performs compound annotation based on library matching and retention index. All compounds were individually reviewed based on ExactMass, retention index delta and library match factor (Figure 2). Canonical Correlation Analysis was performed using the FactoMineR package in R.</p><h4><strong>Conclusions</strong></h4><p>The aligners used in the current study were approved in the late 90s when E&amp;Ls methods were not as prominent or sensitive as they are today. This study stands out with:&nbsp;</p><ul><li>The first report of numerous E&amp;L compounds with known potential adverse effects in a population of clear aligner users&nbsp;</li><li>Providing an insight of the relationships between E&amp;Ls and user’s metadata such as age, DWT and TSS&nbsp;</li><li>Providing the necessary libraries to find parent compounds and their potential metabolites</li></ul><h3><strong>2. EST Analytical: Optimization of 1,4-Dioxane and Ethanol Detection Using USEPA Method 8260</strong></h3><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/Purge_and_Trap_1_4_Dioxane_and_Ethanol_by_8260_App_Note_b669c79f53.pdf"><strong>Full PDF for download</strong></a></li></ul><p>During the manufacture of pharmaceuticals, 1, 4-Dioxane is used as a cleansing agent. It is also a byproduct of plastic manufacturing. The most likely exposure to 1, 4-Dioxane is at an industrial site. However, if any 1, 4-Dioxane is released into the environment during manufacturing there is a potential for it to migrate into ground water. The fact that 1, 4-Dioxane is so miscible in water makes degradation of the chemical challenging. Ethanol, on the other hand, has been a popular gasoline additive. Since it burns more quickly and completely than gasoline, emissions from car exhaust are decreased. The downside of this is underground storage tank leakage and fuel spills cause ground water and drinking water to be contaminated with both the fuel and the ethanol additive. Since ethanol is also very miscible in water, the detection of ethanol contamination in water can be difficult.&nbsp;</p><p>There have been several innovations that help overcome the obstacles of detecting 1, 4-Dioxane and Ethanol. The first one is the SIM mode of the mass spectrometer. This mode allows better detection of hard to extract compounds. Furthermore, mass spectrometers are now equipped to run SIM/Scan, this not only helps detect more difficult compounds, but also enables the detection of an extensive list of USEPA Method 8260 compounds without having to run the samples twice. Advancements in purge and trap sampling have also facilitated better detection of these compounds. Most effective in this has been the ability to heat the samples. However, there are drawbacks to better detection. The most problematic of these is the tendency of 1, 4-Dioxane and Ethanol to “stick” to the glass ware. This susceptibility has caused many headaches in environmental labs.&nbsp;</p><p>This application note will investigate seven variations of purge and trap sampling. The data will then be evaluated in order to recommend the optimum purge and trap sampling parameters for your lab.</p><h4><strong>Experimental</strong></h4><p>The sampling system used for this study was the <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/products/2160"><strong>EST Analytical Evolution concentrator</strong></a> affixed with a Vocarb 3000 trap. The <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/products/2159"><strong>Centurion WS autosampler</strong></a> equipped with the syringe option was employed as the autosampler. The separation and analysis were performed by an <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?manufacturerItems=1&amp;search=7890A"><strong>Agilent 7890A Gas Chromatograph (GC)</strong></a> and <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?manufacturerItems=1&amp;search=5975C"><strong>5975C inert XL Mass Spectrometer (MS)</strong></a>. The GC was configured with a <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?manufacturerItems=9&amp;search=Rxi-624+Sil+MS"><strong>Restek Rxi-624 Sil MS</strong></a> 30m x 0.25mm x 1.4µm column. The purge and trap parameters used for this study are listed in Tables 1 and 2 while Table 3 shows the GC/MS parameters.</p><h4><strong>Conclusions</strong></h4><p>All seven purge and trap parameter iterations passed the USEPA Method 8260 requirements for linearity and method detection limits. The problem with some of the experimental parameters was found in the carryover and precision and accuracy studies. The carryover using the traditional sparge vessel showed a large amount of carryover for the Ethanol and 1, 4-Dioxane. Since the carryover was so high, the precision and accuracy data suffered. The Fritless/Bulbless sparge vessel, on the other hand, displayed much lower carryover for the Ethanol and 1, 4-Dioxane especially when the patented sparge bake was not used. However, the 1, 2, 4-Trichlorobenzene, Naphthalene and 1, 2, 3-Trichlorobenzene carryover after the 50ppb standard was above the lower limit of the curve. Thus, the sparge bake would be recommended in order to limit the carryover of the heavier compounds. The optimum purge and trap parameters proved to be the patented water extraction technique. This technique provided linearity and method detection limits that met the USEPA Method 8260 requirements, while providing excellent precision and accuracy data. During water extraction, the sample is transferred to an empty 40ml vial and then purged in the soil station of the Centurion. The “fresh” vial provides a clean sparge vessel for every sample thus limiting carryover for both the Ethanol and 1, 4-Dioxane and for the heavy compounds. This lack of carryover aided in providing optimum precision and accuracy and carryover results and would be the recommended method for examining these troublesome compounds.</p><h3><strong>3. Shimadzu / ASMS: Quantitation of Acetaldehyde, Ethylene Oxide, 2-Chloroethanol, Ethylene Glycol, 1,4-Dioxane &amp; Diethylene Glycol in PEG 3350 by using dynamic headspace GC-MS/MS</strong></h3><ul><li>Poster</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/ASMS_2025_TP_301_ad1ab4ac3e.pdf"><strong>Full PDF for download</strong></a></li></ul><p>Polyethylene glycol 3350 (PEG 3350) is used to treat occasional constipation and it is in a class of medications called osmotic laxatives. PEG 3350 is an addition polymer of ethylene oxide and water with formula H(OCH2CH2)n OH, in which n represents the average number of oxyethylene groups. The average molecular weight of PEG 3350 is 3015–3685 g/mol (Da). Acetaldehyde, Ethylene Oxide (EtO), 2-Chloroethanol (2-CE), Ethylene Glycol (EG), 1,4- Dioxane and Diethylene Glycol (DEG) are the probable impurities of PEG 3350. All these above impurities are highly toxic &amp; hazardous substances.&nbsp;</p><p>As per the USP monograph, different chromatography techniques and sample preparation methods are used to quantify above mentioned impurities. This study reports a single sensitive and reliable analytical method for quantitation of all above impurities by using dynamic headspace (Trap) coupled with GC-MS/MS system. Limit of impurities and detail method of analysis are shown in table 1.</p><p>This study reports highly sensitive single method for the simultaneous quantification of multiple probable impurities of PEG 3350 by using dynamic headspace (Trap) coupled with triple quadrupole gas chromatography (GC-MS/MS) system.&nbsp;</p><h4><strong>Materials and methods&nbsp;</strong></h4><p>For this study, individual impurity reference standards were procured from Sigma Aldrich, whereas PEG 3350 powder sample was procured from local medical store. 10% of PEG 3350 powder sample solution (as such sample solution) and respective levels of matrixmatched calibration standard solutions were prepared in acetonitrile. Standard addition method was used to quantify impurities in the PEG 3350 sample. This method was part validated with respect to (w.r.t) precision, linearity/accuracy and sample analysis. <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?manufacturerItems=3&amp;search=GCMS-TQ8050+NX"><strong>GCMS-TQ8050 NX</strong></a> equipped with headspace sampler <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?manufacturerItems=3&amp;search=HS-20+NX"><strong>HS-20 NX </strong></a>(Trap) (Figure 1), manufactured by Shimadzu Corporation Japan, was used to quantify impurities in the PEG 3350 sample</p><h4><strong>Conclusion</strong></h4><ul><li>Trace level quantification of Acetaldehyde, EtO, 2-CE, 1,4-Dioxane, EG and DEG in PEG 3350 sample was successfully performed by using Shimadzu GCMS-TQ8050 NX with HS-20 NX (Trap) dynamic headspace sampler.</li><li>Dynamic headspace mode outperforms the current regulatory limits, delivering multifold times more sensitivity compared to other injection techniques.</li><li>Shimadzu GCMS-TQ8050 NX features a new highly efficient detector and superior noise reduction technology that enhance sensitivity and enables quantitation of impurities even at trace levels.</li></ul>

News from LabRulezGCMS Library - Week 38, 2025

Synthesis and Identification of 3-Oxazolines in Cocoa

<p><strong>Our Library never stops expanding. What are the most recent contributions to LabRulezGCMS Library in the week of 16th March 2026? Check out new documents from the field of the gas phase, especially GC and GC/MS techniques!</strong></p><blockquote><p><span style="font-size:20px;">👉 </span><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library"><span style="font-size:20px;"><strong>SEARCH THE LARGEST REPOSITORY OF DOCUMENTS ABOUT GCMS AND 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://icpms.labrulez.com/library"><strong>LabRulezICPMS</strong></a> libraries.</p></blockquote><p>This week we bring you posters by <strong>Agilent Technologies / ASMS </strong>and <strong>MDCW / William &amp; Mary, </strong>application note by<strong> Shimadzu </strong>and other document by <strong>Thermo Fisher Scientific!</strong></p><h3><strong>1. Agilent Technologies / ASMS: Analysis of Extractables and Leachables in Catheters Using Accurate Mass Libraries and High-Resolution GC/MS and LC/MS</strong></h3><ul><li>Poster</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/ps_7250_revident_extractables_leachables_asms_2025_tp_317_en_agilent_e6d3b2e923.pdf"><strong>Full PDF for download</strong></a></li></ul><p>Materials used in the production of medical devices contain substances that have the potential to leach from the devices. Extractables and leachables (E&amp;L) represent a range of structurally diverse compounds including antioxidants, UV absorbers, dyes, catalysts, plasticizers and polymer degradation products. Therefore, both liquid and gas chromatography techniques coupled with mass spectrometry detectors (LC/MS and GC/MS) are utilized to achieve a comprehensive chemical characterization. Application-specific accurate mass libraries combined with an efficient screening workflow, helps to increase confidence in compound identification that saves time on reviewing data while focused on E/L relevant compounds. In this study, we analyzed catheters extracts using high-resolution MS and performed data analysis using accurate mass libraries.</p><h4><strong>Experimental</strong></h4><p>Catheters from three suppliers were used in this study. Catheter A was made from PVC, and did not include DEHP, DINP, BPA or natural rubber latex. Catheter B was made with natural rubber latex base and silicone elastomer coating, and there was no claim to be phthalate or BPA free. Catheter C was a silicone-coated latex catheter made with natural rubber latex base and no DEHP or BPA. E&amp;L standards were obtained from AChemTek. Catheters were extracted with ethanol:water 1:1 solvent at 37 ˚C for 24 and 48 hours as well as 7 days and analyzed using GC/Q-TOF and <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=10&amp;search=Revident+LC%2FQ-TOF"><strong>LC/Q-TOF systems</strong></a>. The GC/MS analysis was performed using the <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=8890+GC"><strong>8890 GC</strong></a> coupled to the <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=7250+GC%2FQ-TOF"><strong>7250 Q-TOF</strong></a> and the new Agilent low bleed DB-5Q column.</p><h4><strong>Results and Discussion</strong></h4><h5><strong>Accurate Mass E&amp;L Library for GC/Q-TOF</strong></h5><p>To create a new Agilent accurate mass E&amp;L Personal Compound Database Library (PCDL) for GC/Q-TOF, over 400 spectra have been collected for E&amp;L compounds. All accurate mass fragment ions in each spectrum have been annotated with formulas based on accurate mass information and isotope ratios (Figure 3). The fragment formula annotations were then verified and converted to the theoretical m/z.</p><h4><strong>Conclusions</strong></h4><ul><li>A combined workflow for the analysis of extractables and leachables by high-resolution GC/MS and LC/MS was developed using catheter extracts.</li><li>Both GC/MS and LC/MS techniques were necessary to cover a comprehensive list of E&amp;L compounds. Although several E&amp;L compounds were detected by<br>both GC/MS and LC/MS, in most cases hydrocarbons, most plasticizers, and some antioxidants were more amenable to GC/MS.</li></ul><h3><strong>2. MDCW / William &amp; Mary: A sustainable approach to nontargeted analysis using hydrogen as a carrier gas for GC×GC</strong></h3><ul><li>Poster</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/P_13_Fisher_2c50f2c420.pdf"><strong>Full PDF for download</strong></a></li></ul><p>Comprehensive two-dimensional gas chromatography (GC×GC) is a separation technique used to separate complex mixtures based on two different retention mechanisms, usually polarity and volatility. A nontargeted approach is commonly used for a separation technique such as GC×GC. This type of approach means that instead of looking for one or two specific components and disregarding the rest of the sample, the whole sample can be viewed exhaustively. This approach is more applicable for forensic cases especially, where the identity or composition of the sample is unknown. It is also a more sustainable approach because only one run is needed to have the full characterization of a sample instead of needing to run a sample multiple times with a different target analyte each time.</p><h4><strong>EXPERIMENTAL</strong></h4><ul><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/products/37"><strong>LECO’s Pegasus BT4D</strong></a> instrument was used for this project.</li></ul><h4><strong>RESULTS</strong></h4><p><strong>AGREEprep Comparisons:</strong> The overall scores for the two methods were 0.44 and 0.52 for helium and hydrogen, respectively. This means that the hydrogen method is more sustainable than the helium method. The criteria breakdown in Figure 6 shows the 10 different criteria used to score the methods, including sample throughput, sample preparation steps, and sustainable material usage, namely carrier gas choice.</p><h4><strong>CONCLUSIONS</strong></h4><p>The Restek EZGZ Method Translator can be used to provide three possible hydrogen methods for any given helium method. After inputting the values of a helium method, the respective hydrogen values are given for three possible methods, each prioritizing something different: translate, efficiency, and speed. The translate method was chosen as the best choice.&nbsp;</p><p>The hydrogen method achieved a higher score on the AGREEprep metric, meaning that this method is more sustainable that the helium method. This better score is solely due to the carrier gas change – everything else in the methods stayed constant.&nbsp;</p><p>Hydrogen as a carrier gas allows for higher sample throughput and faster run times. It can also be a renewable resource, made through the electrolysis of water in a laboratory using a generator.&nbsp;</p><p>A nontargeted approach is inherently greener than a targeted approach because instead of re-running a sample multiple times to analyze a different component each time, the whole picture was captured from the beginning and can be looked at through a different lens to analyze a new component.</p><h3><strong>3. Shimadzu: Analysis of PFAS in Textiles Based on EN 17681-1 and EN 17681-2</strong></h3><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/an_01_01108_en_e04fe25939.pdf"><strong>Full PDF for download</strong></a></li></ul><h5><strong>User Benefits</strong></h5><ul><li>Combining LCMS and GCMS enables the determination of PFAS below threshold limits in textiles.&nbsp;</li><li>Spike recovery test shows good percentage recoveries of all compounds (70–130 %) that are at or below the EU POPs threshold limit (25 ppb).</li><li>LabSolutions software offers integrated control over GCMS and LCMS for more efficient testing and data analysis.</li></ul><p>Per- and polyfluoroalkyl substances (PFAS) are used in a wide range of applications because of their useful properties, such as heat resistance and water repellency. However, PFAS are also extremely stable substances that resist degradation and accumulate in the environment, which has led to concerns about their effects on humans. Since eliminating sources of PFAS is essential to prevent them from accumulating in the environment and in living organisms, many countries are passing laws that restrict the production, distribution, and use of PFAS in products. For example, the EU POPs Regulation sets a permitted threshold of up to 0.025 mg/kg (25 ppb) for certain PFAS (including PFOA, PFOS, and PFHxS) in substances, mixtures, and products<sup>1)</sup>.&nbsp;</p><p>EN 17681 is a European standard that describes methods for determining PFAS in textiles. The EN 17681 standard is divided into two parts according to the target compounds and methods. EN 17681-1 describes an LC/MS/MS method that targets ionic PFAS, and EN 17681-2 describes a GC/MS(/MS) method that targets certain semi-volatile and volatile neutral PFAS. A 2025 revision of EN 17681-1 changed the sample preparation method for more efficient PFAS extraction<sup>2),3)</sup>.&nbsp;</p><p>This Application News describes the analysis of the target compounds shown in Table 1 based on the EN 17681-1 and EN 17681-2 standards, using both LC/MS/MS and GC/MS/MS.</p><h4><strong>&nbsp;EN 17681-1 (LC/MS/MS) Analysis Conditions</strong></h4><p>Analysis was performed using the <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=1&amp;search=LCMS-8050RX"><strong>LCMS-8050RX triple quadrupole mass spectrometer</strong></a> (Fig. 1, left). The analysis conditions used are shown in Table 3. Analyzing PFAS necessitates caution because PFAS can leach from the analytical system, the mobile phase or other sources. PFAS contamination from the system was minimized by attaching a delay column between the mixer and autosampler. The mobile phase was also prepared using PFAS grade reagents.</p><h4><strong>EN 17681-2 (GC/MS(/MS)) Analysis Conditions</strong></h4><p>Analysis was performed using a <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=1&amp;search=GCMS-TQ8050+NX"><strong>GCMS-TQ8050 NX triple quadrupole mass spectrometer</strong></a> (Fig. 1, right) that was equipped with a boosted efficiency ion source (BEIS). The BEIS optimizes the electron beam focus for maximum ionization efficiency, enabling reliable analysis of PFAS at very low levels. The analysis conditions used are shown in Table 4.</p><h4><strong>Results from Analysis of Ski Wear</strong></h4><p>Old ski clothing was used as a sample. The results obtained from analyzing this sample by the EN 17681-1 (LC/MS/MS) method are shown in Fig. 11. To investigate the effect of the EN 17681- 1:2025 update, analysis was performed using both the preupdate (EN 17681-1:2022) and post-update (EN 17681-1:2025) sample preparation methods. The alkaline hydrolysis treatment used by the EN 17681-1:2025 method dramatically increased the amounts of NMeFOSE, 6:2 FTOH, 8:2 FTOH, and 10:2 FTOH that were detected, and these compounds were detected at levels above the upper limit of their respective calibration curve ranges. This shows that PFAS extraction is improved by using the updated EN 17681-1:2025 sample preparation method. Of the 33 compounds targeted by the LC/MS/MS method, 20 were detected in the sample.&nbsp;</p><p>Analyzing the sample by GC/MS/MS using the EN 17681-2 method detected 8 out of the 12 compounds targeted by the EN 17681-2 method. Of these, 8:2 FTOH and 10:2 FTOH were detected at levels above the upper limit of their respective calibration curve ranges (Fig. 12).</p><h4><strong>Conclusion&nbsp;</strong></h4><p>The analysis of PFAS in textiles was performed according to EN 17681-1 and EN 17681-2 standards, utilizing the LCMS-8050RX and GCMS-TQ8050 NX systems. By combining LC/MS/MS analysis and GC/MS analysis, all target compounds were successfully measured at levels of 25 ppb or less. Spike recovery test at the EU POPs threshold limit (25 ppb) also demonstrated good percentage recovery (70–130 %) for all compounds. Results also showed that PFAS extraction was improved by using the EN 17681-1:2025 sample preparation method, which was updated in 2025.</p><h3><strong>4. Thermo Fisher Scientific: Fast on-line monitoring of flare gases</strong></h3><ul><li>Other document</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/fast_on_line_monitoring_of_flare_gases_wp1635_27fa9188ff.pdf"><strong>Full PDF for download</strong></a></li></ul><h4><strong>Measurement of flare gas streams by process mass spectrometry</strong></h4><p>Process mass spectrometry (MS) is particularly suited to the measurement of flare gas streams because it offers accurate, fast, multicomponent analysis. Table 1 shows an example of a flare gas stream containing hydrogen, nitrogen and hydrocarbons up to C6. Analysis of these eleven components will typically be performed in just 20 seconds, allowing one mass spectrometer to monitor more than one flare, depending on the distances involved. Alternatively, one MS can be used to measure process streams and flare streams, even though the composition and concentrations may be very different.</p><h4><strong>Advantages of magnetic sector MS&nbsp;</strong></h4><p>Thermo Fisher Scientific manufactures both quadrupole and magnetic sector mass spectrometers. Over thirty years of industrial experience have shown the magnetic sector based analyzer offers the best performance for industrial online gas analysis. <strong>Thermo Scientific™ Prima PRO process mass spectrometers</strong> (Figure 1) offer ideal capabilities for industrial gas analysis.&nbsp;</p><p>Key advantages of magnetic sector analyzers include improved precision, accuracy, long intervals between calibrations and resistance to contamination. Typically, analytical precision is between 2 and 10 times better than a quadrupole analyzer, depending on the gases analyzed and complexity of the mixture.&nbsp;</p><p>Neutral gas atoms and molecules are first converted into positively charged ions in the Prima PRO MS ion source. This is an enclosed type for high sensitivity, minimum background interference and maximum contamination resistance. It is a high-energy (1000 eV) analyzer that offers extremely rugged performance in the presence of gases and vapors that have the potential for contaminating the internal vacuum components. Prima PRO MS has a proven track record of monitoring high percent level concentrations of organic compounds without experiencing drift or contamination.</p><p>Ions are then accelerated through a flight tube, where they are separated by their mass to charge ratios in a magnetic field of variable strength. Since the magnetic sector mass spectrometer produces a focused ion beam at the detector, the peak shape obtained is ‘flat-topped’ and uniform response is observed over a finite mass width. As the height of the peak is directly proportional to the number of ions striking the detector it is also directly proportional to the concentration of the component being measured. As long as the measurement is taken anywhere on the peak’s flat top, high precision analysis will be observed.</p><p>The Prima PRO MS’ ability to measure over a wide dynamic range is critically important if the varying composition levels in flare gas are to be measured accurately. The Prima PRO MS has been independently evaluated by EffecTech UK, an independent specialist company providing accredited calibration and testing services to the energy and power industries for gas quality, flow and total energy metering. It is accredited to internationally recognized ISO/IEC 17025:2005 standards; this specifies the general requirements for the competence to carry out tests and/ or calibrations, including sampling.</p><h4><strong>Summary&nbsp;</strong></h4><p>Magnetic sector MS, as evidenced by the Prima PRO process MS performance, provides fast, accurate on-line analysis of flare gas composition. The inherent power of magnetic sector mass spectrometry, combined with the flexibility of GasWorks software, enables one Prima PRO MS to monitor not only flare gas streams, but also multiple process streams. Root cause fault analysis is therefore greatly facilitated, by comparing the detailed composition data from the flare gas stream with that of the various process streams. As well as complete compositional analysis, Prima PRO MS provides accurate fuel gas properties, including LHV, HHV, density, specific gravity, Wobbe Index, stoichiometric air requirement and CARI. This ensures waste gases are burnt to complete combustion and unburned pollutants are not emitted from the flare.</p>

News from LabRulezGCMS Library - Week 12, 2026

<p><strong>Our Library never stops expanding. What are the most recent contributions to LabRulezGCMS Library in the week of 20th July 2026? Check out new documents from the field of the gas phase, especially GC and GC/MS techniques!</strong></p><blockquote><p><span style="font-size:20px;">👉 </span><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library"><span style="font-size:20px;"><strong>SEARCH THE LARGEST REPOSITORY OF DOCUMENTS ABOUT GCMS AND 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://icpms.labrulez.com/library"><strong>LabRulezICPMS</strong></a> libraries.</p></blockquote><p>This week we bring you posters by <strong>Agilent Technologies / ASMS,&nbsp;</strong> <strong>Bruker / ASMS</strong>, presentation by <strong>MDCW / University of North Dakota </strong>and application note by <strong>Shimadzu!</strong></p><h3><strong>1. Agilent Technologies / ASMS: Extractables Analysis of Food Contact Materials Using High-Resolution GC/MS and LC/MS</strong></h3><ul><li>Poster</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/po_fcm_extractables_lc_q_tof_wp_311_asms_2026_en_agilent_f5d83c8730.pdf"><strong>Full PDF for download</strong></a></li></ul><section><div><div><div><div><div><div><p>Chemicals residing in food contact materials (FCM) can migrate from packaging and containers into food. The FCM include a variety of materials including paper and plastic among others. The substances that migrate from FCM include volatile, semi-volatile and non-volatile compounds and therefore a combination of GC/MS and LC/MS techniques is needed for comprehensive analysis of potential migrants. In this study we evaluated different types of FCM including food vacuum sealer bags, heavy duty plastic food containers as well as lined paperboard containers. Various solvents were assessed for their ability to extract different classes of food packaging-derived chemicals. For increased confidence in compound annotation, high-resolution GC and LC MS platforms were used in this study in combination with application-specific accurate mass libraries.</p><h4><strong>Experimental</strong></h4><h5><strong>GC/Q-TOF&nbsp;</strong></h5><ul><li><strong>MS:</strong> <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?from=1990&amp;mainauthorItems=10&amp;search=7250&amp;to=2026"><strong>Agilent 7250 GC/Q-TOF</strong></a></li><li><strong>GC: </strong><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?from=1990&amp;mainauthorItems=10&amp;to=2026&amp;search=8890"><strong>Agilent 8890 GC</strong></a></li><li><strong>Column: </strong><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?from=1990&amp;mainauthorItems=10&amp;to=2026&amp;search=DB-5Q"><strong>Agilent DB-5Q</strong></a>, 30 m, 0.25 mm, 0.25 µm</li></ul><h5><strong>LC/Q-TOF</strong></h5><ul><li><strong>LC: </strong><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=10&amp;search=1290+Infinity+II"><strong>Agilent 1290 Infinity II</strong></a></li><li><strong>MS: </strong><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=10&amp;search=Revident"><strong>Agilent Revident LC/Q-TOF</strong></a></li><li><strong>Analytical column:</strong> <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=10&amp;search=Poroshell+Aq-C18"><strong>Agilent Poroshell Aq-C18</strong></a> 2.1 x 150 mm, 2.7µm column</li></ul><h4><strong>Conclusions</strong></h4><p>FCM extractions were optimized and successfully analyzed using a variety techniques based on highresolution GC/MS and LC/MS. Combination of different high resolution MS techniques helped to ensure a comprehensive E&amp;L compound coverage. E&amp;L focused accurate mass libraries were key to efficient data analysis.</p><h3><strong>2. Bruker / ASMS: Novel data processing workflow including in-silico derivatization for integrated CI &amp; EI MS data acquired with the GC-ecTOF instrument</strong></h3><ul><li>Poster</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/asms_2026_thp_429_in_silico_derivatization_for_integrated_ci_ei_ectof_fb022d26ba.pdf"><strong>Full PDF for download</strong></a></li></ul><section><div><div><div><div><div><div><p>Combined suspect and non-target GC-MS analysis of volatile and semi-volatile compounds holds relevance for environmental monitoring &amp; research, food, flavor &amp; fragrance analysis as well as metabolomics studies. The combination of Chemical Ionization (CI) and Electron Ionization (EI) in the ecTOF instrument (Bruker Daltonics, Bremen, Germany) can improve the identification confidence of unknown compounds, especially in complex samples and when no standards are available. The simultaneous usage of two complementary ionization techniques brings additional advantages for quantification workflows. To leverage these benefits, a novel data processing approach has been developed, and applicability is shown in two study designs.</p><h4><strong>Methods</strong></h4><p>Derivatized samples from two studies were analyzed using the GC-ecTOF instrument. Data were converted to TSF format and processed with prototype versions of MetaboScape and TASQ. Untargeted feature detection was performed on the CI data stream, including de-isotoping, de-adducting for CI-specific ions [M-H]⁺, [M]⁺, [M+H]⁺, [M+NH₄]⁺, [M-CH3 ] + and retention time alignment across all samples.</p><h4><strong>Conclusion</strong></h4><ul><li>Untargeted feature finding and streamlined annotation of ecTOF supported by in-silico derivatization and in-silico fragmentation extends GC-MS analysis for metabolomics and non-target screening.&nbsp;</li><li>In-silico derivatization permits complementary annotation for compounds lacking reference standards.&nbsp;</li><li>Simplified process from identified markers in profiling experiments to target screening and quantitation methods.</li></ul><h3><strong>3. MDCW / University of North Dakota: Identifying the transition from ante-mortem to post-mortem odor in cadavers cadavers in an outdoor environment</strong></h3><ul><li>Presentation</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/O_23_Patel_2a1bb7a2fa.pdf"><strong>Full PDF for download</strong></a></li></ul><section><div><div><div><div><div><div><p>This presentation investigates how the characteristic odor of a human body changes during the transition from life (ante-mortem) to decomposition (post-mortem). The researchers focused on identifying volatile organic compounds (VOCs) released during the early post-mortem period and determining when the scent profile changes from that of a living person to that associated with human remains. Understanding this transition is particularly important for improving search and rescue operations, where distinguishing between living victims and deceased individuals is essential for deploying search-and-rescue dogs and human remains detection dogs effectively.</p><p>To study this process, VOC samples were collected from body donors at both a morgue and an outdoor decomposition research facility (REST). Air samples were collected using sorbent tubes and ACTI-VOC pumps after controlled VOC accumulation and sampling periods. Chemical analysis was performed using <strong>thermal desorption comprehensive two-dimensional gas chromatography coupled with mass spectrometry (TD-GC×GC-MS)</strong>. The analytical system employed a Restek <strong>Rxi®-624Sil MS</strong> first-dimension column and a <strong>Stabilwax®</strong> second-dimension column, with electron ionization (70 eV) mass spectrometry covering a mass range of <strong>29–300 amu</strong> at an acquisition rate of <strong>250 spectra/s</strong>. Data processing combined <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/products/41"><strong>ChromaTOF</strong></a> software with <strong>RStudio</strong> for feature alignment, normalization, filtering, and manual verification of VOC profiles.</p><p>The study identified <strong>827 volatile organic compounds</strong>, representing a wide range of chemical classes including nitrogen-containing compounds, esters, halogenated compounds, aromatics, alcohols, ketones, aldehydes, sulfur-containing compounds, ethers, and acids. By comparing experimentally detected VOCs with compounds previously reported in the literature for both living humans and decomposing remains, the researchers identified <strong>33 trans-mortem VOCs</strong> that characterize the transition between ante-mortem and post-mortem odor. VOC profiles were then monitored throughout decomposition for individual donors, allowing the team to visualize how the relative contributions of ante-mortem, trans-mortem, and post-mortem compounds evolved over time.</p><p>The results showed that ante-mortem and trans-mortem VOCs remained detectable during the earliest stages after death, while post-mortem odor compounds became increasingly dominant after approximately <strong>Accumulated Degree Days (ADD) 73.4</strong>, corresponding to <strong>Experimental Day 3</strong>. The authors conclude that although these findings improve our understanding of early decomposition odor chemistry, additional studies across different environments and seasonal conditions are needed to standardize VOC-based approaches and further support forensic investigations and search-and-rescue applications.</p><h3><strong>4. Shimadzu: Gas Analysis for CO2 Conversion Using a GI-30 Auto Gas Injector</strong></h3><ul><li>Application note</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/an_01_00964_en_2482908145.pdf"><strong>Full PDF for download</strong></a></li></ul><p>The catalytic conversion of carbon dioxide (CO2) to methanol (MeOH) and to hydrocarbons has garnered significant attention as a strategy to realize a sustainable chemical industry. Analytical targets in CO2 conversion studies typically include carbon monoxide (CO), hydrocarbons, alcohols, and other reaction products. Selection of appropriate column and detector combinations must therefore be guided by the nature and concentrations of target analytes.</p><p>In this application news, we demonstrate simultaneous analysis on two parallel columns by using INJ2-way branch unit to permit detection of CO and hydrocarbons together with alcohols such as MeOH. We also present a simplified measurement approach employing a single-column configuration equipped with a thermal conductivity detector(TCD).</p><h4><strong>System Configuration and Analysis Conditions</strong></h4><p>Two reaction schemes using CO2 as feedstock were envisaged: (1) MeOH synthesis and (2) conversion to hydrocarbons. The instrumentation comprised the <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?from=1990&amp;mainauthorItems=1&amp;to=2026&amp;search=GI-30"><strong>Auto Gas Injector GI-30</strong></a> and the SPI inlet, which minimizes air ingress and sample adsorption (Fig. 1).&nbsp;</p><p>For the MeOH synthesis application, a Jetanizer -FID—which permits detection of CO and CO2 that are not observable by a conventional FID—was employed. A MICROPACKED-ST packed column provides separation of CO from O2 (ambient contamination); however, higher-boiling hydrocarbons and alcohols such as MeOH are not eluted from this column. To achieve comprehensive analysis, the injector was splitted and an SH-Q-BOND capillary column was used to resolve hydrocarbons and MeOH concurrently. The injection-port splitting is implemented using dedicated hardware (Application News No. 01-00661-EN).&nbsp;</p><p>For the conversion to hydrocarbons scenario, when analytes are permanent gases and C3-or-smaller hydrocarbons, quantitative analysis can be performed with a single MICROPACKED-ST column coupled to a TCD. The TCD responds to differences in thermal conductivity between carrier and analyte gases; measuring low–thermal-conductivity species such as hydrocarbons requires a carrier gas with high thermal conductivity (helium or hydrogen) (Table 1). The <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?from=1990&amp;mainauthorItems=1&amp;search=gc-2050&amp;to=2026"><strong>Brevis</strong> <strong>GC-2050</strong></a><strong> TCD</strong> uses a single filament design, resulting in rapid baseline stabilization (~10 minutes), which is advantageous for routine operation.</p><h4><strong>Conclusion</strong></h4><p>Using INJ2-way branch unit enables simultaneous analyses using distinct column-detector combinations within a single chromatographic cycle, permitting comprehensive quantification of reaction products from CO2 conversion— ranging from CO and hydrocarbons to alcohols such as MeOH. For analyses restricted to hydrocarbons up to C3, a streamlined single-column TCD configuration provides sufficient separation and sensitivity. It should be noted that MeOH and hydrocarbons of carbon number ≥ C4 may adsorb or be retained on the MICROPACKED-ST column; periodic column conditioning is therefore recommended.</p></div></div></div></div></div></div></section></div></div></div></div></div></div></section></div></div></div></div></div></div></section>

News from LabRulezGCMS Library - Week 30, 2026

<div><div><section><div><div><div><div><div><div><p><strong>This study introduces a highly sensitive compound-specific isotope analysis method for identifying protein binders in aged paintings. Using direct inlet pyrolysis-GC-combustion-isotope ratio mass spectrometry (DIP-GC-C-IRMS), the method targets δ13C values of pyrolytic diketopiperazines and reduces the required sample size from milligrams to micrograms.</strong></p><p>Reference materials showed that diketopiperazine isotope signatures preserve the distinction between terrestrial and marine collagen sources. Analysis of two 16th-century Italian paintings yielded values consistent with terrestrial animal glue, demonstrating that these isotopic markers can survive aging and degradation and support minimally destructive analysis of cultural heritage objects.</p></div></div></div></div></div><div><blockquote><h4><strong>The original article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/ancham/article/98/29/21183/5211080/Pyrolysis-Compound-Specific-Isotope-Analysis-of?searchresult=1"><strong>Pyrolysis Compound-Specific Isotope Analysis of Proteins in Aged Paintings: Diketopiperazine δ13C Values as Collagen Source Indicators&nbsp;</strong></a></h4><p>Eugenia Geddes da Filicaia* ; David A. Peggie; Iain P. Kendall; Ian D. Bull; Richard P. Evershed</p><p>Anal. Chem. (2026) 98 (29): 21183–21196.</p><p>&nbsp;<a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1021/acs.analchem.5c07901">https://doi.org/10.1021/acs.analchem.5c07901</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><div><div><p>The complexities and challenges presented by the analysis of protein paint binders illustrate the need for novel methods of identification for these materials, in particular to distinguish between terrestrial and fish-animal glues. An alternative approach with great potential may be found in the neighboring field of archeology, where collagen in bones and teeth has been used as a palaeodietary indicator since the 1970s. Determination of bulk δ<sup>15</sup>N values may suggest the position of an organism in the respective food web, while δ<sup>13</sup>C values offer insight into their diet. (<a href="javascript:;">27−29</a>) Bulk δ<sup>13</sup>C and δ<sup>15</sup>N values of collagen are weighted averages of the δ<sup>13</sup>C and δ<sup>15</sup>N values of their constituent AAs, which reflect both dietary sources and metabolic processes. Serine, glycine, and alanine (Ser, Gly, and Ala) are part of the glucogenic AA group, which is biosynthesized from intermediates of glycolysis. As pyruvate is the end product of glycolysis, considered the catabolic pathway of carbohydrates, the isotopic signature of these AAs should reflect that of dietary carbohydrates. Aspartic acid and glutamic acid (Asp and Glu), asparagine (Asn), and Pro are part of the ketogenic AA group, originating from intermediates of the tricarboxylic acid (TCA) cycle. Due to their TCA cycle precursors, the isotopic signature of these AAs should reflect that of the whole diet, if biosynthesized <i>de novo</i>. Finally, Hyp and hydroxylysine cannot be incorporated into proteins from the diet and are formed after the polypeptides are synthesized, during posttranslational processing of collagen. Hydroxylysine is formed from lysine (Lys), whereas Hyp results from hydroxylation of Pro residues. (<a href="javascript:;">30</a>) Moreover, AAs in the “trophic group“ tend to display a large enrichment in <sup>15</sup>N with increasing trophic level, unlike those belonging to the “source group.“</p></div><div><p>Significant limitations therefore surround the interpretation of bulk stable isotope ratios, which, however, may be overcome by compound-specific isotope analysis (CSIA). Individual AA δ<sup>13</sup>C values have proven invaluable for distinguishing terrestrial from marine diets of our ancestors, (<a href="javascript:;">30−35</a>) while AA δ<sup>15</sup>N values are being increasingly used in archeological trophic position studies. (<a href="javascript:;">36−39</a>) Despite the similarity in target material, CSIA has never been extended to the analysis of animal glue, or any other protein, in paintings. Reasons for this are likely linked to the sample sizes required for standard protocols for GC-combustion-isotope ratio MS (GC-C-IRMS), which, however, as illustrated by recent studies, (<a href="javascript:;">40−42</a>) may be significantly reduced by undertaking direct inlet pyrolysis (DIP)-GC-C-IRMS. Here, this technique is applied to the analysis of proteins of paintings, in particular by targeting, for the first time, the stable carbon isotope composition of DKPs, protein pyrolysates. Having confirmed that DKPs reflect the isotopic signature of their constituent AAs, DKP δ<sup>13</sup>C values may be used to distinguish terrestrial from aquatic animal glue in aged paintings.</p><h4><strong>Materials and Methods</strong></h4><h5><strong>Instrumental Analyses</strong></h5><div><p>For elemental analysis (EA)-IRMS, GC-FID, and GC-C-IRMS methods, please see SI1. All chromatograms were replotted in RStudio. DIP-GC-MS was carried out on an <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=7890A"><strong>Agilent Technologies 7890A GC</strong></a> coupled to an <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=5975C"><strong>Agilent Technologies 5975C MSD</strong></a> (Agilent Technologies, Santa Clara, CA, USA), a single quadrupole MS. The GC was equipped with a nonpolar fused-silica capillary column (30 m × 0.25 mm i.d. × 0.25 μm film thickness) with a BPX5 stationary phase (5% phenyl polysilphenylene-siloxane, SGE) and a TSP in the multimode inlet (MMI), operated in splitless mode. The initial TSP temperature was 50 <span>°</span>C, set to rise to 450 <span>°</span>C (900 <span>°</span>C min<sup>–1</sup>, 3 min isothermal hold), before cooling to 250 <span>°</span>C (25 <span>°</span>C min<sup>–1</sup>, 40 min isothermal hold). The oven temperature began at 40 <span>°</span>C, was increased to 200 <span>°</span>C (10 <span>°</span>C min<sup>–1</sup>), and then to 310 <span>°</span>C (6 <span>°</span>C min<sup>–1</sup>) with a final hold time of 20 min. He was used as a carrier gas at a constant flow (1.2 mL min<sup>–1</sup>).</p></div><div><p>The MS was set to acquire in full scan mode (<i>m</i>/<i>z</i> 50–650) at 0.2 scan s<sup>–1</sup>, and was operated at an EI potential of 70 eV with a solvent delay of 6.5 min. The MS transfer line temperature was set to 280 <span>°</span>C, the ion source temperature to 230 <span>°</span>C, and the quadrupole to 150 <span>°</span>C. Data acquisition was undertaken using Agilent Technologies Chemstation, and data processing with Agilent Technologies MassHunter software (version 10.0) and the AMDIS deconvolution software (NIST, version 2.66). Peaks were identified using a combination of mass spectral information, GC retention times (RTs), and comparison to the NIST mass spectral library (Mass Spectral Search Program version 2.0 and NIST 08 MS Library), published data sets, and NG databases. An <i>n</i>-alkane “ladder“ (with a characteristic bell-shaped peak profile) standard, containing C<sub>7</sub>–C<sub>40</sub> saturated alkanes (0.01 mg mL<sup>–1</sup> in <i>n</i>-hexane), was used to monitor instrument performance.</p></div><div><p>DIP-GC-QTOF-MS analysis was carried out on an <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=7890B"><strong>Agilent Technologies 7890B GC</strong></a> coupled to an <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=7200"><strong>Agilent Technologies 7200 Accurate Mass QTOF MS</strong></a> (Agilent Technologies, Santa Clara, CA, USA). The same method was used, except that the MMI was held at 450 <span>°</span>C for 1 min only. The MS was set with an acquisition rate of 5 spectra s<sup>–1</sup>, an acquisition time of 200 ms spectrum<sup>–1</sup>, and an emission current of 2.1 μA. DIP-GC-C-IRMS analysis was carried out on an <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=8890"><strong>Agilent Technologies 8890 GC</strong></a> coupled to an <strong>Elementar isoprime precisION IRMS</strong> via an Elementar GC5 combustion interface, using a combustion reactor containing CuO pellets and Ag wool (Elementar Analysensysteme GmbH, Hanau, Germany), maintained at 850 <span>°</span>C. The GC parameters were identical to those for DIP-GC-MS, except that the MMI, after being held at 450 <span>°</span>C for 3 min, was cooled to 300 <span>°</span>C (900 <span>°</span>C min<sup>–1</sup>, isothermal hold for 50 min). Additionally, the oven program was typically shortened by setting a lower maximum temperature (280 <span>°</span>C instead of 310 <span>°</span>C), where it was held for 10 min. He was used as a carrier gas at a constant flow (2 mL min<sup>–1</sup>).</p></div></div></div></div></div></div></section></div></div><h4><strong>Results and Discussion</strong></h4><h5><strong>Pyrolytic Marker Identification from DIP-GC-MS of Protein References</strong></h5><div><p>The thermal degradation of intact proteins has been shown to be a multistep reaction, (<a href="javascript:;">45</a>) where the formation of DKPs, occurring in the first degradation step (<i>T</i><sub>max</sub> = 325 <span>°</span>C), does not require high Py temperatures. (<a href="javascript:;">21</a>) Protein markers may therefore be detected through DIP-GC-MS, as testified by the analysis of a soapstone fragment from Qarmaaluit (18th–19th century CE). (<a href="javascript:;">46</a>) Nonetheless, given that this technique is not widely reported in the literature, modern protein references were analyzed by DIP-GC-MS, and pyrolytic profiles obtained were compared to published Py-GC-MS data. Studies have been undertaken with (<a href="javascript:;">22, 47, 48</a>) and without (<a href="javascript:;">22, 26</a>) TMAH, hence, both methods were carried out here. Results were scrutinized, in particular, to identify pyrolytic markers suitable for DIP-GC-C-IRMS analysis. Egg yolk, which presents a similar AA composition as egg white, was not examined, as its high fat content was deemed to interfere with the analysis.</p></div><div><p>In general, DIP-GC-MS analyses involving derivatization with TMAH, in particular for animal glues, featured many more compounds compared to the total ion chromatograms (TICs) obtained without derivatization (see <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/ancham/article-supplement/5211080/pdf/ac5c07901_si_001/">Figure S1</a> for G1, aged gelatin spread). In this case, GC-MS TICs exhibited better baseline separation with the most abundant peaks corresponding to the targeted DKPs. Further analysis of glue samples was therefore carried out without derivatization, as good baseline resolution is central to reliable compound-specific stable isotope determinations. (<a href="javascript:;">43</a>) Analysis of rabbit skin glues (GRS1 and GRS2) and isinglass glues (GI1 and GI2) yielded GC-MS TICs identical to each other. In accordance with the literature, (<a href="javascript:;">21, 22, 49</a>) as illustrated in <a href="javascript:;">Figure 1</a>a, they are dominated by peaks corresponding to diketodipyrrole (peak 8) and cyclo(Pro-Gly) (peak 10). Because of its relatively high polarity, or overloading, the latter produces a broad (fronting) peak. (<a href="javascript:;">50</a>)</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Anal_Chem_2026_98_29_21183_21196_Figure_1_Partial_DIP_GC_QTOF_MS_total_ion_chromatograms_TI_Cs_for_a_isinglass_GI_2_b_casein_C1_and_c_egg_white_EW_1_f4442d8498.jpg" alt="Anal. Chem. (2026) 98 (29): 21183–21196: Figure 1. Partial DIP-GC-QTOF-MS total ion chromatograms (TICs) for (a) isinglass, GI2, (b) casein, C1, and (c) egg white, EW1. Information on relevant DKPs (in purple) and other peaks (in pink) is listed in Table S1." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Anal_Chem_2026_98_29_21183_21196_Figure_1_Partial_DIP_GC_QTOF_MS_total_ion_chromatograms_TI_Cs_for_a_isinglass_GI_2_b_casein_C1_and_c_egg_white_EW_1_f4442d8498.jpg 127w," sizes="100vw" width="1500" height="1840"></p></div><h5><strong>DIP-GC-C-IRMS for Source Determination of Proteins in Paintings from The National Gallery</strong></h5><div><p>Ground layer samples from two Italian Renaissance paintings in the National Gallery collection, NG599 (Madonna of the Meadows) and NG6368 (Tanaquil), were analyzed by GC by White in the 1980s. (<a href="javascript:;">15</a>) The author reported AA profiles consistent with the presence of animal glues, which, for this purpose, would be expected to be of terrestrial origin. However, given the low proportion of Pro and Hyp in NG6368, White discussed a possible aquatic origin for this glue. Analysis was repeated with the aforementioned DIP techniques, revealing very similar profiles to those of the reference animal glues (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/ancham/article-supplement/5211080/pdf/ac5c07901_si_001/">Figure S6</a>). The protein binder in the ground layers of both paintings exhibited similar DKP stable carbon isotope signatures. In particular, δ<sup>13</sup>C<sub>Pro-Gly</sub> values were determined to be −18.4‰ (±0.1) and −17.6‰ (±0.1) for NG599 and NG6368, respectively. The δ<sup>13</sup>C<sub>Pro-Hyp</sub> values were found to equal −19.8‰ (±0.4) and −18.6‰ (±0.001), respectively.</p></div><div><p>It should be noted that the SD observed for these determinations is lower than what was reported for some of the reference binders discussed above. These errors are in line with those observed for standard GC-C-IRMS methods. As these paint fragments were in the form of very fine powder, typical of paint samples, these results support that sample inhomogeneities might be primarily responsible for wide SDs, rather than the DIP-GC-C-IRMS method itself. In the case of marine animal glues, more enriched δ<sup>13</sup>C<sub>DKP</sub> values would be expected than those observed here, especially for cyclo(Pro-Gly). Instead, the determined δ<sup>13</sup>C<sub>DKP</sub> values suggest a terrestrial origin for the glues in both paintings. Indeed, by plotting the values as described above, as shown in <a href="javascript:;">Figure 7</a>, both paintings fall extremely close to the reference rabbit skin glues. Hence, for NG599, these results are in agreement with the previous analysis by White (1984). However, regarding the origin of the binder from NG6368, these findings support a similar terrestrial origin, suggesting that a lower-than-average concentration of Pro and Hyp is not characteristic of fish glues.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Anal_Chem_2026_98_29_21183_21196_Figure_7_a_d13_C_Pro_Gly_values_for_the_ground_layers_from_paintings_NG_599_purple_star_and_NG_6368_pink_star_bb585e6957.jpg" alt="Anal. Chem. (2026) 98 (29): 21183–21196: Figure 7. (a) δ13CPro-Gly values for the ground layers from paintings NG599 (purple star) and NG6368 (pink star), against their δ13CPro-Hyp values. Modern references for marine (GI1 and GI2) and terrestrial (GRS1 and GRS2) animal glues are in gray. (b) Corresponding Δ13C(Pro-Gly)–(Pro-Hyp) values against their δ13CPro-Gly values. The error bars represent the SD on either side (±) of the value. The δ13C values have been corrected to take into account post-Industrial Revolution effects of burning fossil fuels by the addition of 1.2‰. (68) Instrumental precision was 0.3‰." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Anal_Chem_2026_98_29_21183_21196_Figure_7_a_d13_C_Pro_Gly_values_for_the_ground_layers_from_paintings_NG_599_purple_star_and_NG_6368_pink_star_bb585e6957.jpg 72w," sizes="100vw" width="625" height="1349"></p><p>Although a wider range of reference material needs to be analyzed before this method may be reliably used, these results indicate that DIP-GC-C-IRMS is able to differentiate between terrestrial and marine animal glues in painting samples. Given the challenges currently faced by this field to differentiate fish glues from other animal glues, this innovative technique might enable new information to be gathered on artist techniques and the history of use of these materials. It is important to note that the method can be applied to many other fields of research. In addition to painting analysis, this minimally invasive protocol is pertinent to any discipline that involves the analysis of degraded proteins, heterogeneous and complex matrices, or where access to samples is restricted due to ethical implications or lack of material. This includes environmental and forensic sciences, paleo- and zooarcheology, paleoecology, and anthropology.</p></div><h4><strong>Conclusions</strong></h4><div><p>Aged proteins encountered in painted cultural heritage have usually undergone extreme structural changes from the freshly applied material, often rendering unambiguous protein source determination unattainable. In particular, the distinction between terrestrial and aquatic animal glues is typically not possible without proteomics approaches. Nonetheless, this paper demonstrates that, with minimal sample sizes, DIP-GC-C-IRMS permits determination of δ<sup>13</sup>C values of DKPs arising from pyrolysis of aged proteinaceous material, providing the first record of the isotopic signature of these compounds. In this study, δ<sup>13</sup>C values of DKPs were shown to reflect the δ<sup>13</sup>C values of the parent AAs and, therefore, to permit unambiguous differentiation between terrestrial and marine animal glues, analogous to the use of CSIA of archeological collagen for palaeodietary reconstruction.</p></div><div><p>Remarkably, DIP-GC-C-IRMS, requiring a considerably smaller sample (in the microgram range) than typical GC-C-IRMS methods (in the milligram range), renders CSIA accessible for the investigation of proteinaceous material in painted cultural heritage for the first time. This widens the application of CSIA to precious, unique, and fragile objects in cultural heritage and beyond. Moreover, the rapidity of the analysis places DIP-GC-C-IRMS as a useful screening method to identify materials of interest for further proteomic analyses.</p></div><div><p>First, the isotopic imprint of modern references for rabbit skin glues, isinglass glues, casein, chicken, and duck eggs was confirmed through established EA-IRMS and GC-C-IRMS methods. As expected, bulk and individual AA δ<sup>13</sup>C and δ<sup>15</sup>N values for terrestrial animal glues exhibited a higher depletion in <sup>13</sup>C and <sup>15</sup>N than the marine glues. The δ<sup>13</sup>C values of DKPs arising from DIP-GC-C-IRMS of the same materials were found to retain this relationship. Furthermore, the ground layers of two 16th-century Italian paintings from the National Gallery collection, known to contain animal glue, yielded δ<sup>13</sup>C<sub>DKP</sub> values consistent with the terrestrial variety, confirming that the isotopic signature of these compounds is retained through aging and degradation.</p></div>

Pyrolysis Compound-Specific Isotope Analysis of Proteins in Aged Paintings: Diketopiperazine δ13C Values as Collagen Source Indicators

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