🎤Francis Femi OloyIn this episode of Concentrating on Chromatography, David speaks with Francis Femi Oloy about using chromatography to uncover hidden pollutants in real-world water systems.Femi’s team analyzed polychlorinated biphenyls (PCBs) in six major rivers in southwestern Nigeria — compounds that were banned decades ago but still persist in the environment. Using a workflow that many analytical labs will recognize — liquid–liquid extraction, cleanup, rotary evaporation, nitrogen blowdown, and GC-ECD detection — they quantified 25 PCB congeners at trace levels and linked the results to ecological and human health risk.<h4>In this conversation, we cover:</h4><ul><li>Why legacy pollutants like PCBs still show up today</li><li>Choosing GC-ECD vs LC-MS for halogenated compounds</li><li>Liquid–liquid extraction and matrix cleanup strategies</li><li>Why sample concentration is critical for dilute environmental samples</li><li>How rotovap + nitrogen blowdown work together without losing volatile analytes</li><li>Seasonal trends (why wet season levels were higher)</li><li>Translating concentration data into meaningful risk assessments</li></ul><h3>Video Transcription</h3><section><div><div><div><div><div><div>Persistent organic pollutants such as polychlorinated biphenyls (PCBs) remain a significant environmental concern despite decades of regulatory restrictions. In this interview, Francais Femi Oloy discusses the environmental and analytical challenges associated with monitoring PCB contamination in rivers of southwestern Nigeria, a rapidly industrializing region where urban growth, industrial activity, agriculture, and dense populations intersect with extensive aquatic systems.Oloy explains that his interest in environmental contaminant analysis emerged from observing unexplained health problems and environmental degradation while growing up in Nigeria. This motivated his transition into organic and environmental chemistry, with a focus on identifying pollutants present in drinking water, agricultural soils, and food systems. Southwestern Nigeria, particularly the Lagos region, represents a critical environmental monitoring area due to intense industrial development, shipping activity, and widespread human dependence on rivers for domestic use, agriculture, and fishing.Although PCBs are considered “legacy pollutants” and are no longer intentionally produced, the interview highlights why they continue to persist in aquatic environments. Old electrical transformers and aging industrial equipment still contain PCB residues, while historical contamination stored in river sediments can become remobilized during flooding, dredging, or sediment disturbance. Because PCBs are hydrophobic and resistant to degradation, they preferentially accumulate in sediments and bioaccumulate through aquatic food chains, creating long-term environmental and human exposure risks.A major focus of the discussion centers on the analytical workflow used for PCB determination in environmental water samples. Composite river water samples were collected in amber glass bottles to avoid contamination and photodegradation, preserved with sodium azide to minimize microbial activity, and stored under cooled conditions prior to extraction. The analytical protocol employed liquid–liquid extraction using dichloromethane (DCM) and hexane to recover both polar and nonpolar PCB congeners. Oloy emphasizes that liquid–liquid extraction was selected over solid-phase extraction (SPE) because of concerns about congener retention within sorbent materials and clogging issues associated with large-volume environmental samples.Following extraction, concentration and cleanup represented critical analytical stages due to the trace-level occurrence and volatility of PCBs. Silica and alumina cleanup procedures were used to remove matrix interferences prior to instrumental analysis. The concentration workflow combined rotary evaporation for bulk solvent reduction with nitrogen blowdown for final volume reduction to less than 1 mL, while carefully avoiding excessive temperature or complete dryness to minimize analyte loss. Oloy repeatedly stresses that improper concentration procedures are among the most common causes of analytical failure in PCB analysis.For instrumental determination, the study utilized gas chromatography coupled with electron capture detection (GC-ECD) rather than LC-MS or GC-MS. According to Oloy, GC was preferred because PCBs are sufficiently volatile for gas chromatographic separation, while ECD provided superior sensitivity and selectivity for chlorinated compounds at environmentally relevant concentrations. The interview also discusses analytical validation strategies, including the use of surrogate standards to assess recoveries, which ranged from approximately 85% to 114%, and signal-to-noise-based determination of detection limits.The study further examined seasonal variations in PCB concentrations, revealing higher levels during the wet season. This observation was attributed to rainfall-driven runoff from contaminated infrastructure, sediment resuspension, and lower temperatures that reduce volatilization losses. To communicate toxicological relevance beyond simple concentration reporting, the researchers also calculated toxic equivalency values (TEQs), converting mixtures of PCB congeners into biologically meaningful toxicity estimates comparable to dioxin toxicity metrics.Beyond environmental monitoring, Oloy highlights broader research interests focused on pollutant remediation and sustainable environmental protection. His group is also involved in developing catalytic materials capable of degrading or removing persistent contaminants from environmental systems. Throughout the discussion, he emphasizes that analytical chemistry plays a central role not only in detecting pollutants, but also in enabling prevention, remediation, and long-term environmental management strategies.</div></div></div></div></div></div></section><blockquote>This text has been automatically transcribed from a video presentation using AI technology. It may contain inaccuracies and is not guaranteed to be 100% correct.</blockquote><blockquote><h4>Concentrating on Chromatography Podcast</h4>Dive into the frontiers of chromatography, mass spectrometry, and sample preparation with host David Oliva. Each episode features candid conversations with leading researchers, industry innovators, and passionate scientists who are shaping the future of analytical chemistry. From decoding PFAS detection challenges to exploring the latest in AI-assisted liquid chromatography, this show uncovers practical workflows, sustainability breakthroughs, and the real-world impact of separation science. Whether you’re a chromatographer, lab professional, or researcher you'll discover inspiring content!You can find Concentrating on Chromatography Podcast in podcast apps:<ul><li><a target="_blank" rel="noopener noreferrer" href="https://open.spotify.com/show/1wZg67rCjoGju4yhqxI3tL">Spotify</a></li><li><a target="_blank" rel="noopener noreferrer" href="https://podcasts.apple.com/tz/podcast/concentrating-on-chromatography/id1788429185">Apple podcast</a></li><li><a target="_blank" rel="noopener noreferrer" href="https://podscan.fm/podcasts/concentrating-on-chromatography">podscan</a></li></ul>and on <a target="_blank" rel="noopener noreferrer" href="https://www.youtube.com/@ChromatographyTalk/videos">YouTube channel</a></blockquote>

Tracking Toxic PCBs in River Water using Gas Chromatography–Electron Capture Detection

This study presents a high-temperature GC-APCI-MS/MS method for detecting large polycyclic aromatic hydrocarbons in pyroplastics and environmental samples. The approach enables sensitive analysis of PAHs with molecular weights from 314–424 Da without extensive cleanup or fractionation.Application to pyroplastics from the M/V X-Press Pearl fire revealed substantially elevated levels of large PAHs compared to unburnt plastics. Several compounds, including 1,3,5-triphenylbenzene, emerged as promising markers for identifying pyroplastic contamination, supporting future monitoring of plastic burning, fires, and microplastic pollution.<blockquote><h4>The original article</h4><h4><a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c11703">Gas Chromatography-Atmospheric Pressure Chemical Ionization (GC-APCI) Expands the Analytical Window for Detection of Large PAHs (≥24 Ringed-Carbons) in Pyroplastics and Other Environmental Matrices</a></h4>Cara Megill, Douglas M. Stevens*, Christopher M. Reddy, Bryan D. James*, Robert K. Nelson, and Frank L. DormanACS Omega 2026, 11, 7, 12321–12329<a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1021/acsomega.5c11703">https://doi.org/10.1021/acsomega.5c11703</a><h6>licensed under <a target="_blank" rel="noopener noreferrer" href="https://creativecommons.org/licenses/by/4.0/">CC-BY 4.0</a></h6></blockquote>Selected sections from the article follow. Formats and hyperlinks were adapted from the original.<div>The measurement and reporting of polycyclic aromatic hydrocarbons (PAHs) are routine practices in environmental monitoring and risk assessment. <a href="javascript:void(0);">(1−3)</a> However, of the thousands of PAHs, only the 16 designated as Priority Pollutants by the U.S. Environmental Protection Agency (EPA16) are typically reported. <a href="javascript:void(0);">(4,5)</a> These span two to six ringed parent PAHs, ranging in molecular weight from 128 to 278 Da. It is well recognized that this limited analyte list drastically simplifies and misses a significant fraction of PAHs. <a href="javascript:void(0);">(4)</a> For example, the concentration of C1–C4 alkylated PAHs can be greater than or equal to the concentration of the EPA16 in crude oils and fuels. <a href="javascript:void(0);">(6)</a> Expanding the analytical window of PAHs has proven valuable for forensic analysis of oil spills (e.g., alkylated and heterocycle-containing PAHs) and relevant for toxicological evaluation(e.g., oxygen-, nitrogen-, and sulfur-containing PAHs). <a href="javascript:void(0);">(3,7)</a> Moreover, the sources of PAHs have distinct compositions of PAHs, <a href="javascript:void(0);">(1,8)</a> which enables the use of PAHs for source apportionment. <a href="javascript:void(0);">(2,7)</a> Including alkylated and sulfur-containing PAHs (those beyond the EPA16) in the investigation of environmental samples and other matrices provides greater discriminating power between potential sources (using extracted ion chromatograms). <a href="javascript:void(0);">(3,7,9)</a> Additionally, monitoring the compositional changes of PAHs in the environment can inform about the fate and environmental processing of the matrix (e.g., oil weathering). <a href="javascript:void(0);">(2)</a> While these efforts have made strides in considering other PAHs, an environmentally relevant fraction of PAHs remains underutilized.PAHs with more than six rings have been reported in diverse environmental matrices. <a href="javascript:void(0);">(10,11)</a> These large PAHs (≥24 ringed-carbons <a href="javascript:void(0);">(10)</a>) have been found in combustion-derived particulate matter, <a href="javascript:void(0);">(12−19)</a> urban dust, <a href="javascript:void(0);">(20−23)</a> refinery deposits, <a href="javascript:void(0);">(11)</a> coal tars and pitches, <a href="javascript:void(0);">(24−27)</a> cokes, <a href="javascript:void(0);">(28)</a> soils, <a href="javascript:void(0);">(20,22)</a> sediments, <a href="javascript:void(0);">(20−23)</a> and deep-sea hydrothermal vent bitumen. <a href="javascript:void(0);">(29)</a> Most reports of large PAHs in environmental matrices have been from analyses of U.S. National Institute of Standards and Technology (NIST) standard reference materials (SRMs); <a href="javascript:void(0);">(18,21−23,25,26,30)</a> a few 302 Da isomers have been certified in three SRM. <a href="javascript:void(0);">(31)</a> Nonetheless, isomers ranging from 326 to 374 Da have been reported in SRMs for urban dust (1649a/b), diesel particulate (1650b and 2975), coal tar (1597a), and marine sediment (1941b), displaying qualitative differences between the sources in their large PAH compositions; <a href="javascript:void(0);">(18,20,22,23,27)</a> thus, large PAHs should offer forensic utility.Recent advances in soft ionization within an atmospheric pressure chemical ionization source for gas chromatography–mass spectrometry (GC-APCI) are well-suited for the analysis of large PAHs. Two contributing factors for this are the tolerance for high carrier gas flow rates by GC-APCI and the sensitivity of charge exchange APCI for aromatic species. <a href="javascript:void(0);">(48)</a> Increasing the carrier gas flow rate reduces the elution temperature of analytes, making many higher mass analytes accessible using a conventional GC and column, although poor thermal stability may still pose challenges for some analytes. <a href="javascript:void(0);">(49)</a> Classic vacuum-source GC/MS systems using electron ionization (EI) restrict the upper carrier gas flow allowed from the GC, and therefore, cannot fully utilize high GC carrier gas flows. The sensitivity of GC-APCI for components of petroleum, such as PAHs, has been previously reported. <a href="javascript:void(0);">(48)</a> Furthermore, unlike LC-APCI, which commonly exhibits protonation of analytes in positive ion mode, <a href="javascript:void(0);">(50)</a> GC-APCI+ can operate with dry source conditions. These conditions result in nitrogen-mediated charge exchange ionization and ions of the form M+•, the same form of molecular ion created using EI. As a result, because the charge site location on an ion dictates which product ions will be stable, the same multiple reaction monitoring (MRM) transitions can be used for both GC-APCI MS/MS and EI MS/MS. <a href="javascript:void(0);">(51)</a>Herein, a GC-APCI method was developed for the detection of large PAHs. Due to the limited availability of pure standards, previously characterized NIST SRMs were used in method development as sources of large PAHs. The values of the method and detection of large PAHs were demonstrated by analyzing environmental plastic samples collected after the M/V X-Press Pearl ship fire and plastic spill.<h4>Materials and Methods</h4><h5>GC-APCI</h5>The solvent extracts and dilutions were analyzed by GC-APCI on a <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/554">Xevo TQ Absolute</a> (Waters Corporation) tandem quadrupole mass spectrometer (TQ-MS/MS). The atmospheric pressure gas chromatography (APGC) ionization source was operated in charge transfer mode using dry N2 as the reagent gas. Dry N2 reagent gas creates molecular ions of the form M+• with no significant adduct formation for large PAHs. The high reagent gas flow rate of 350 mL/min into the ionization chamber, combined with low energies applied to the transfer optics from the atmospheric pressure region to the first quadrupole, leads to a high molecular ion survival rate. Furthermore, the use of MS/MS with quadrupoles operating at unit mass resolution prevents potential effects on response caused by adduct formation. Acquisitions were performed in positive ion, MRM mode. Two MRM transitions were used for each of the 16 precursor masses, ranging from 314 to 424 Da (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acsomega.5c11703/suppl_file/ao5c11703_si_001.pdf">Table S1</a>). No optimization of source conditions specific to the analysis of large PAHs was required. The list of 16 specific precursor masses targeted in this range was developed using multiple sources reporting large PAHs in NIST SRMs and samples from deep-sea hydrothermal vents. <a href="javascript:void(0);">(18,29,30)</a> The two transitions represented constant neutral losses of 2 and 4 Da at high collision energies of 60–100 eV, using N2 as the collision gas.For 1,3,5-TPB analysis, the APGC ionization source was operated in charge transfer mode using N2 as the collision gas. Acquisitions were performed in positive ion, MRM mode, yielding six MRM transitions for analysis (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acsomega.5c11703/suppl_file/ao5c11703_si_001.pdf">Table S2</a>). Similar to the large PAHs, this analyte also shows neutral losses of 2 and 4 Da, reflecting behavior like that of the more condensed structures.The <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=8890+GC">8890 GC (Agilent Technologies)</a> was configured with N2 as the carrier gas and an <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=7&amp;search=Rxi-5HT">Rxi-5HT column (Restek)</a> of 15 m in length, 0.25 mm inner diameter, and 0.10 μm film thickness. The split/splitless (SSL) injection port was operated at a 10:1 split ratio with a temperature of 380 °C. A 1 μL injection volume was used for all analyses. The temperature program was 30.8 min; it started by holding at 40 °C for 0.5 min, then ramped to 160 °C at 14 °C/min, followed by a ramp to 395 °C at 22 °C/min and a hold at the temperature for 11 min. The flow rate of the N2 carrier gas was initially 0.60 mL/min, then ramped at 0.015 mL/min2 to 0.90 mL/min, followed by a ramp at 0.150 mL/min2 to 3.0 mL/min. To adapt the system for high-temperature work, the SSL was configured with a high-temperature septum (400 °C maximum), a 100% graphite liner O-ring, and a straight 4 mm inner diameter, wool-packed liner (450 °C maximum). Additional instrument and method details are included in the <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acsomega.5c11703/suppl_file/ao5c11703_si_001.pdf">Supporting Information</a>.<h4>Results</h4><h5>Analysis of Large PAHs in Pyroplastic Samples by GC-APCI</h5>Macroplastic and microplastic debris from the M/V X-Press Pearl ship fire and plastic spill were investigated for the presence and distribution of large PAHs. The field samples included white, unburnt polyethylene nurdles and two types of pyroplastic, termed burnt plastic and combustion remnant (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c11703#fig1">Figure 1</a>), both of which were polyethylene. <a href="javascript:void(0);">(43)</a> The types of pyroplastics were previously operationally defined based on the size and shape of the pieces. <a href="javascript:void(0);">(43)</a>Investigation of the 302 Da isomers revealed profiles similar to those of the SRMs; however, unique differences were observed (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acsomega.5c11703/suppl_file/ao5c11703_si_001.pdf">Figure S2</a>). Eighteen to twenty-one peaks were detected across the plastic samples. Compared with the SRMs, the pyroplastics showed decreases in the relative abundance of dibenzo[a,e]fluoranthene and increases in dibenzo[a,h]pyrene (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acsomega.5c11703/suppl_file/ao5c11703_si_001.pdf">Figure S2</a>). This trend was not the case for the white nurdle sample. Starting at a retention time of 16.80 min, two peaks were unique to the pyroplastic samples (not present in the SRMs and especially minor in the white nurdles). These peaks followed that for dibenzo[a,h]pyrene, which had previously been reported as the last detected 302 Da isomer compound in the SRMs, <a href="javascript:void(0);">(21)</a> supporting their novelty as marker compounds of pyroplastics.The plastic samples displayed similarities and differences in the presence and distribution of large PAHs (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c11703#fig3">Figure 3</a>). The white nurdles, burnt plastic, and combustion remnant all contained high-intensity peaks at 20.50 min for 398 Da and 19.55 min for 374 Da. Peaks between 20.00 and 20.25 min of 398 Da and the 19.35 min peak of 374 Da were reduced in intensity for the pyroplastics compared to the white nurdles (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acsomega.5c11703/suppl_file/ao5c11703_si_001.pdf">Figure S3</a>). Conversely, the peaks between 18.50 and 18.75 min of 350 Da were more intense in the pyroplastics compared to the white nurdles.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/ACS_Omega_2026_11_7_12321_12329_Figure_3_Comparison_of_the_resolved_isomers_for_398_374_and_350_Da_of_the_white_nurdles_burnt_plastic_and_combustion_remnant_pieces_ec390ebae3.jpg" alt="ACS Omega 2026, 11, 7, 12321–12329: Figure 3. Comparison of the resolved isomers for 398, 374, and 350 Da of the white nurdles, burnt plastic, and combustion remnant pieces collected from Pamunugama Beach, Sri Lanka, following the 2021 M/V X-Press Pearl ship fire and plastic spill." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_ACS_Omega_2026_11_7_12321_12329_Figure_3_Comparison_of_the_resolved_isomers_for_398_374_and_350_Da_of_the_white_nurdles_burnt_plastic_and_combustion_remnant_pieces_ec390ebae3.jpg 232w," sizes="100vw" width="1600" height="1077">The levels of all the targeted large PAHs were at least 2 orders of magnitude higher in the pyroplastics than in the white nurdles. These levels included the individual PAHs that were common to the pyroplastics. This trend mirrored that observed for smaller PAHs and the solvent-extractable content of the sample types. <a href="javascript:void(0);">(39,43,46)</a> There were also slight differences in the signatures of the large PAHs found in the pyroplastics. The 398 Da peak at 20.24 min, along with the 374 Da peak at 19.31 min and the 350 Da peak at 18.61 min, were more prominent in the combustion remnant compared to the burnt plastic (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acsomega.5c11703/suppl_file/ao5c11703_si_001.pdf">Figure S3</a>).Similar to the differences in large PAH signatures between the SRMs, the plastic samples had different signatures. Such qualitative interpretation of extracted ion chromatograms is forensically accepted for distinguishing sources. <a href="javascript:void(0);">(3)</a> This feature can potentially be utilized to differentiate between plastic types (e.g., virgin, weathered, and partially combusted) as well as to identify sources of the large PAHs and the combustion temperature.<h4>Conclusions</h4>GC-APCI-MS/MS proved a useful technique for detecting large PAHs in diverse environmental matrices, including extracts from pyroplastic field samples. Despite a lack of widely available analytical standards for large PAHs, NIST SRMs provided ample material for method development for their detection. Nonetheless, with the increasing research on microplastics in the environment and their relevance to human health, an environmental SRM with certified values for large PAHs is needed, and pyroplastics may provide such a source of material. Large PAHs and 1,3,5-TPB were detected in pyroplastic field samples and hold promise as chemical markers for pyroplastics, complementing other means for their detection in environmental samples (e.g., appearance and physical properties). Due to the accessibility of GC-APCI, the detection of large PAHs can be integrated into workflows for evaluating environmental samples, including those for microplastics.</div>

Gas Chromatography-Atmospheric Pressure Chemical Ionization (GC-APCI) Expands the Analytical Window for Detection of Large PAHs (≥24 Ringed-Carbons) in Pyroplastics and Other Environmental Matrices

In the week of May 11, the following webinars await you in the field of gas / solid phase and especially Raman, FTIR, GC and GC/MS.<blockquote><h4><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinars">👉 DETAILS AND REGISTRATION IN THE WEBINARS SECTION</a></h4>👉 Search and filter in the largest global database with over 5 500 GC, LC, MS and spectroscopy webinars.</blockquote><h5>1. Thermo Fisher Scientific: Uncovering Microplastics: Identification, Quantification, and Exposure Assessment</h5><ul><li>Tu, 12.5.2026 08:00 CEST</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinar/6136">Registration</a></li></ul>In this webinar, we will explore complementary analytical solutions for comprehensive microplastics characterization.<h5>2. AZoM: From Lab to Line: Leveraging GC and Process MS for Petrochemical Gas Analysis</h5><ul><li>We, 13.5.2026 16:00 CEST</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinar/6171">Registration</a></li></ul>Explore how GC and process MS work together in petrochemical workflows, combining detailed lab analysis with real-time gas monitoring for faster decisions.<h5>3. Milestone: Modern Sample Prep for Organic Contaminants: PAHs, PFAS, MOSH/MOAH in Food</h5><ul><li>We, 13.5.2026 16:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinar/5822">Registration</a></li></ul>Learn how microwave-assisted extraction streamlines food analysis of PAHs, PFAS, and MOSH/MOAH, improving recoveries, reducing solvents, and meeting regulatory demands.<h5>4. Thermo Fisher Scientific: End-to-end automation in GC/GC-MS: Trends, tools, and practical implementation</h5><ul><li>We, 13.5.2026 18:00 CEST</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinar/6186">Registration</a></li></ul>In this GC/GC-MS power hour session, we’ll explore how automation is transforming laboratories by helping teams do more with less time, fewer resources, and greater confidence.<h5>5. GERSTEL: Automating Food Safety Workflows for the Analysis of Edible Oils and Fats</h5><ul><li>We, 13.5.2026 20:00 CEST</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinar/6168">Registration</a></li></ul>Learn how automated workflows improve data quality in edible oil testing, including FAMEs, MOSH/MOAH, and 3-MCPD analysis with real-world insights.

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Organomation, founded in 1959, designs and manufactures high-quality nitrogen evaporators and extraction systems. Known for innovation and durability, their lab instruments are used globally for efficient sample preparation with strong customer support.

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LECO Paradigm Flow Modulator and Shift Flow Splitter

Paradigm RFF Flow Modulator with Shift Flow Splitter boosts GC×GC peak capacity while maintaining constant MS/FID split ratios, enabling accurate, repeatable quantitation across full volatility ranges.

The Paradigm Flow Modulator with Reverse Fill-Flush (RFF) technology dramatically expands chromatographic peak capacity across the full volatility range while preserving quantitative accuracy. The RFF modulator fills a fixed-volume sample loop with effluent from the first-dimension column and then rapidly flushes it onto an orthogonal second-dimension stationary phase. This true comprehensive GC×GC transfer ensures excellent repeatability, robust quantitation, and high-quality separations for complex samples.<h3>Key features</h3><ul><li>Reverse Fill-Flush (RFF) modulation for true comprehensive GC×GC with complete analyte transfer</li><li>Novel chromatography splitter with two channels of pressure assistance</li><li>Designed for high flows required for RFF modulation (≈20 mL/min)</li><li>Constant MS/FID split ratio maintained throughout the entire run, including oven temperature ramps</li></ul><h3>ChromaTOF makes modulation simple</h3>Paradigm eliminates complex offline flow calculations. Integrated <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/products/41">ChromaTOF® software</a> automatically performs all required calculations via a straightforward interface. The resulting methods are optimized to deliver complete analyte transfer, excellent peak shapes, and high chromatographic resolution—without manual trial-and-error.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/LECO_Chromatof_flow_calculation_6b8ca60f99.jpg" alt="LECO Paradigm Flow Modulator and Shift Flow Splitter: ChromaTOF Software identifies method calculation improvements for RFF modulation" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_LECO_Chromatof_flow_calculation_6b8ca60f99.jpg 245w," sizes="100vw" width="670" height="426"><h3>A shift forward in chromatographic analyses</h3>The Shift Flow Splitter introduces a novel splitting mechanism that maintains a constant split ratio between MS and FID across the full GC oven program. Compared to traditional splitters, Shift delivers superior quantitative accuracy with minimal internal standardization, greatly simplifying compound-level and group-type quantitation in GC and GC×GC workflows.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/LECO_LECO_Paradigm_G_Cx_GC_prutokovy_modulator_a_Shift_splitter_5_245c7c2fde.jpg" alt="LECO Paradigm Flow Modulator and Shift Flow Splitter: Close-up on the Shift Flow Splitter installed in a GC oven" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_LECO_LECO_Paradigm_G_Cx_GC_prutokovy_modulator_a_Shift_splitter_5_245c7c2fde.jpg 245w," sizes="100vw" width="2925" height="825"><h3>Software-optimized detector performance</h3>ChromaTOF automatically balances and optimizes the flow directed to TOFMS and FID, ensuring proper peak shapes and matched sensitivity for reliable qualitative and quantitative results.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/LECO_Optimize_flow_e51d505415.jpg" alt="LECO Paradigm Flow Modulator and Shift Flow Splitter: ChromaTOF Software automatically optimizes flow rates" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_LECO_Optimize_flow_e51d505415.jpg 207w," sizes="100vw" width="808" height="608">

LECO QuadJet™ SD

GC×GC-FID system combining thermal modulation and ChromaTOF software to reduce coelution bias, boost resolution, and deliver accurate quantitation of complex samples—without sacrificing productivity.

The QuadJet SD is a comprehensive GC×GC-FID solution designed to reveal the true chemical composition of complex real-world samples. By combining the universal sensitivity of flame ionization detection (FID) with the dramatically increased chromatographic resolution of comprehensive two-dimensional gas chromatography (GC×GC), QuadJet SD minimizes coelution-driven bias and delivers a far more accurate representation of sample composition than conventional one-dimensional GC.Unlike straight GC-FID, where unresolved peaks inflate detector response and introduce systematic error, GC×GC separates compounds using two orthogonal mechanisms within a single run. True GC×GC instruments—such as the QuadJet SD from LECO—use active modulation to quantitatively slice the effluent from the first column and refocus it onto the second column. This approach preserves quantitative integrity while unlocking orders-of-magnitude gains in peak capacity and signal-to-noise ratio.<h3>Key Benefits</h3><ul><li>Enhanced separation power for highly complex mixtures</li><li>Reduced noise and bias error compared to conventional GC-FID</li><li>Integrated <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/products/41">ChromaTOF-based software</a> for acquisition, processing, classification, and reporting in one environment</li><li>Classification tools that simplify component identification</li><li>Cryogen-free modulation option eliminates the need for liquid nitrogen dewars</li></ul><h3>Theory of Operation</h3>In GC-FID analysis, compound quantitation relies on peak area. As sample complexity increases—diesel fuels being a classic example with thousands of constituents—the likelihood of coelution rises sharply. Coeluting compounds produce artificially elevated FID responses, leading to high-bias errors.GC×GC overcomes this limitation by performing two independent chromatographic separations in a single experiment. Thanks to the orthogonal selectivity of the two columns, compounds that coelute in the first dimension are efficiently separated in the second. In the QuadJet SD, eluting peaks from the primary column are quantitatively segmented by the modulator and cryo-focused before entering the secondary column, generating extremely narrow second-dimension peaks—often as short as 50 ms—while maintaining accurate quantitation.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/LECO_Quad_Jet_SD_2_bbb51b2254/LECO-QuadJettm-SD-2_l.webp" alt="LECO: QuadJet™ SD 2 – Processing of acquired GC×GC data using LECO ChromaTOF software" width="923" height="543"><h3>Thermal Modulation</h3>Thermal modulation represents the highest-performance approach for GC×GC, and LECO’s implementation sets the benchmark for ruggedness, reliability, and analytical performance. The QuadJet SD employs a dual-stage, quad-jet thermal modulator positioned between the two columns. This design enables on-column cryo-focusing, dramatically improving peak detectability and resolving power, and delivering an order-of-magnitude improvement in signal-to-noise.For laboratories seeking lower operating costs and simplified workflows, a consumable-free thermal modulator (no liquid nitrogen) is available. This option maintains excellent performance for moderately volatile compounds while eliminating cryogen handling.<h3>Modulators and Instrument Options</h3><ul><li>Thermal modulator choices:<ul><li>Liquid-nitrogen-cooled thermal modulator</li><li>Consumable-free thermal modulator</li></ul></li><li>Optional inlets: S/SL, PTV, and MMI</li></ul>Designed with productivity in mind, the QuadJet SD combines ease of use with an industry-leading secondary oven for the second-dimension column. For laboratories ready to move beyond conventional GC and truly see what has been hidden by coelution, QuadJet SD delivers the next dimension in analytical insight.

LECO GCxGC FLUX flow modulator

Flux GC×GC flow modulator simplifies GC×GC analysis using diverting flow principles. It offers robust, cost-effective modulation without cryogens, ideal for complex, concentrated samples.

Our innovative Flux GC×GC flow modulator was designed with one goal in mind—to make GC×GC more routine, accessible, and easier for you. The flow modulator's concept is based on the sound and easily understood principles first articulated by Seeley et al. on diverting flow. This extraordinarily simple design comprising of a cross shape and sideways T, is not only easy to setup and get started, but its ease-of-use makes it the most cost-effective option for GC×GC analysis.This flow-based modulator is perfect for those who want to perform robust GC×GC analysis, but who don't need the sensitivity of standard quad jet thermal modulation. Ideal samples should be complex, but relatively concentrated. Appropriate applications include petroleum and fragrance analyses such as the classic weathered crude oil example pictured below, which shows a GC×GC plot generated on our Pegasus® BT platform using the Flux flow modulator.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/ee943ea0acb34a8d9c5b72e7ace10666/obrazek_l.webp" alt="LECO GCxGC FLUX flow modulator" width="957" height="523"><h4>Theory of Operation: Diverting Flow</h4>The first and secondary capillary columns are connected together through a simple tube with a fixed gap between the columns. A flow of gas (helium) is then used to inject into the second column or divert to waste. The precision timing and flows are all handled by our integrated software, therefore you just have to click one button to setup and begin performing flow modulation GC×GC on our Pegasus BT platform.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/508b477dd1604d15855f26d786d5b1e4/obrazek_l.webp" alt="LECO GCxGC FLUX flow modulator" width="1026" height="488">Furthermore, no complex spreadsheets are needed to understand your method. This simple and robust design does not require cryogens to carry out GC×GC, which saves time and boosts efficiency in your lab.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/6796d4581c894291b9fab0088753cb8b/obrazek_l.webp" alt="LECO GCxGC FLUX flow modulator" width="918" height="545">

LECO QUADJET Thermal Modulator

Consumable-free dual-stage thermal jet modulator for GC×GC delivering on-column cryo-focusing, higher peak detectability, superior separation, and reliable performance without liquid nitrogen.

The QUADJET Thermal Modulator from LECO delivers industry-leading performance for comprehensive two-dimensional gas chromatography (GC×GC). Compared to alternative thermal or valve-based modulators, QUADJET stands out for its exceptional ruggedness, long-term reliability, and superior modulation efficiency.This GC×GC modulation system uses a dual-stage thermal jet modulator positioned between the first- and second-dimension columns. The design enables true on-column cryo-focusing, significantly enhancing peak sharpness, detectability, and separation power—especially for co-eluting compounds in complex sample matrices.<h3>Key benefits</h3><ul><li>Highest modulation performance for GC×GC Enhances peak detectability and improves separation of co-eluting compounds.</li><li>Dual-stage thermal jet design Provides efficient trapping and re-injection between columns.</li><li>On-column cryo-focusing Improves sensitivity and separation of closely eluting analytes.</li><li>Exceptional robustness and reliability Designed for routine, long-term GC×GC operation.</li></ul><h3>Thermal modulation without liquid nitrogen</h3>Unlike traditional cryogenic modulators, the QUADJET thermal modulator is consumable-free. It delivers the full performance benefits of thermal modulation without the need for liquid nitrogen, eliminating cryogen costs, logistical complexity, and downtime—while maintaining consistent, high-quality results.The QUADJET Thermal Modulator is an ideal choice for laboratories seeking maximum GC×GC performance with minimal operational burden, particularly in demanding applications involving highly complex samples.

Products from category Advanced technologies focused on GCxGC distributed by LECO Instrumente Plzeň - page 1

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