Scientists at IOCB Prague are uncovering new details of gene transcription. They have identified a previously unknown molecular mechanism by which the transcription of genetic information from deoxyribonucleic acid (DNA) into ribonucleic acid (RNA) can be initiated. The researchers focused on a specific class of molecules known as alarmones, which are found in cells across a wide range of organisms and whose levels often increase under conditions of cellular stress. The results were published in the prestigious scientific journal Nature Chemical Biology.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/UOCHB_Vyzkum_z_UOCHB_odhaluje_dosud_nepoznany_zpusob_prepisu_geneticke_informace_bc2bfffa6c.jpg" alt="IOCB Prague/Tomáš Belloň: Research from IOCB Prague reveals a previously unknown mechanism of genetic transcription: Dr. Hana Cahová, head of the Chemical Biology of Nucleic Acids research group." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_UOCHB_Vyzkum_z_UOCHB_odhaluje_dosud_nepoznany_zpusob_prepisu_geneticke_informace_bc2bfffa6c.jpg 234w," sizes="100vw" width="2000" height="1335"><div>Molecules of ribonucleic acid can carry a variety of chemical modifications at one end, known as caps. In eukaryotic organisms, including human cells, the best-known cap plays an important role in RNA stability and in regulating its subsequent fate. In recent years, however, it has become clear that alternative, non-canonical RNA caps also exist, although their formation and the mechanisms by which they are attached to RNA remain only partially understood. These include alarmone caps, formed by dinucleoside polyphosphate molecules, that protect cellular RNA at moments when the cell is under threat.In their study, <a target="_blank" rel="noopener noreferrer" href="https://cahova.group.uochb.cz/en">Dr. Hana Cahová</a> and colleagues examined bacterial RNA polymerase and investigated how this enzyme can initiate transcription using dinucleoside polyphosphates (NpNs) instead of the standard RNA building blocks. For the first time, the scientists described, at the atomic level, how RNA bearing an alarmone cap can be generated directly at the initiation of gene transcription. They also observed that NpNs bind through a different type of base pairing than is typically observed.The work was significantly shaped by Valentina Serianni from Hana Cahová’s team, who demonstrated the ability of dinucleoside polyphosphates to initiate gene transcription, and by Jana Škerlová, who focused on the structural analysis of RNA polymerase. Using cryogenic electron microscopy data, she showed how dinucleoside polyphosphate molecules bind within the active site of RNA polymerase – that is, the core of the enzyme where genetic information is transcribed. Together, their findings help to elucidate the processes that accompany the transcription of genetic information from DNA to RNA.Hana Cahová adds: “We’re describing something that truly occurs in cells and that we’re now able to observe directly at the level of individual molecules. This allows us to answer fundamental questions about cellular processes, such as how cells adapt to stress. RNA plays a central role in this, as it carries the cascade of information underlying any cellular response – for example, to threatening conditions caused by nutrient deprivation or temperature shock.”<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/UOCHB_Vyzkum_z_UOCHB_odhaluje_dosud_nepoznany_zpusob_prepisu_geneticke_informace_2_0fe88ff9e9.jpg" alt="IOCB Prague/Tomáš Belloň: Research from IOCB Prague reveals a previously unknown mechanism of genetic transcription: Dr. Tomáš Kouba, head of the Cryogenic Electron Microscopy core facility." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_UOCHB_Vyzkum_z_UOCHB_odhaluje_dosud_nepoznany_zpusob_prepisu_geneticke_informace_2_0fe88ff9e9.jpg 234w," sizes="100vw" width="2000" height="1335"><div>Cryogenic electron microscopy (cryo-EM) was central to the project. This part of the work was led by Dr. Tomáš Kouba, one of the authors of the study. “Cryogenic electron microscopy allows us to freeze biological molecules in a state very close to their natural form and then determine their three-dimensional structure. This makes it possible to look directly into the active centers of enzymes and observe their function down to the atomic level,” he explains.Last year, IOCB Prague opened a new <a target="_blank" rel="noopener noreferrer" href="https://cryoem.group.uochb.cz/en">cryo-EM center</a> that is unique within the Czech research environment. State-of-the-art cryogenic electron microscopes are housed in a specially designed building and enable the study of biological processes with exceptional structural precision.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/UOCHB_Vyzkum_z_UOCHB_odhaluje_dosud_nepoznany_zpusob_prepisu_geneticke_informace_3_4d881e7a58.jpg" alt="IOCB Prague: Research from IOCB Prague reveals a previously unknown mechanism of genetic transcription: This work shows how NpnNs initiate bacterial transcription. Cryo-EM reveals how nucleobases pair with the template: one in canonical and one in reverse Watson–Crick mode, providing a structural basis for their function as non-canonical RNA caps." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_UOCHB_Vyzkum_z_UOCHB_odhaluje_dosud_nepoznany_zpusob_prepisu_geneticke_informace_3_4d881e7a58.jpg 245w," sizes="100vw" width="2000" height="1077"><blockquote><h4>The Original article</h4><h4><a target="_blank" rel="noopener noreferrer" href="https://www.nature.com/articles/s41589-025-02134-5">Molecular insight into 5′ RNA capping with NpnNs by bacterial RNA polymerase</a></h4>Valentina M. Serianni, Jana Škerlová, Anna Knopp Dubánková, Anton Škríba, Hana Šváchová, Tereza Vučková, Anatolij Filimoněnko, Milan Fábry, Pavlína Řezáčová, Tomáš Kouba &amp; Hana Cahova&nbsp;Nat. Chem. Biol. 21 (2026)<a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1038/s41589-025-02134-5">https://doi.org/10.1038/s41589-025-02134-5</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><h4>Abstract</h4>RNA capped with dinucleoside polyphosphates has been discovered in bacteria and eukaryotes only recently. The likely mechanism of this specific capping involves direct incorporation of dinucleoside polyphosphates by RNA polymerase as noncanonical initiating nucleotides. However, how these compounds bind into the active site of RNA polymerase during transcription initiation is unknown. Here, we explored transcription initiation in vitro, using a series of DNA templates in combination with dinucleoside polyphosphates and model RNA polymerase from Thermus thermophilus. We observed that the transcription start site can vary on the basis of the compatibility of the specific template and dinucleoside polyphosphate. Cryo-electron microscopy structures of transcription initiation complexes with dinucleoside polyphosphates revealed that both nucleobase moieties can pair with the DNA template. The first encoded nucleotide pairs in a canonical Watson–Crick manner, whereas the second nucleobase pairs noncanonically in a reverse Watson–Crick manner. Our work provides a structural explanation of how dinucleoside polyphosphates initiate RNA transcription.</div></div>

Research from IOCB Prague reveals a previously unknown mechanism of genetic transcription

In the week of February 9, 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 5 000 GC, LC, MS and spectroscopy webinars.</blockquote><div><div><div><div><div><div><h5>1. Thermo Fisher Scientific: Process Raman – A Reliable and Versatile Tool for Downstream Process Monitoring and Control for mAb Production</h5><ul><li>Tu, 10.2.2026 16:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinar/5808">Registration</a></li></ul>The presentation highlights how process Raman spectroscopy offers several advantages over traditional in-line UV-Vis analysis for process monitoring and metabolite production control in mAb manufacturing.<h5>2. Wasson-ECE Instrumentation: The Data Driven Plant – How AI Transforms Chemical Manufacturing</h5><ul><li>Tu, 10.2.2026 21:30 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinar/5744">Registration</a></li></ul>Explore how artificial intelligence is applied to improve process efficiency, monitoring, and decision-making in modern chemical manufacturing.<h5>3. New Food Magazine: The Science of Next-Gen Ingredients – Fermentation, Formulation and Function</h5><ul><li>We, 11.2.2026 16:00 CET</li><li><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinar/5720">Registration</a></li></ul>Discover how fermentation-driven innovation is transforming functional food ingredients, with analytical insights to optimize flavour, functionality, and product stability.</div></div></div></div></div></div>

Webinars LabRulezGCMS Week 07/2026

This study presents an analytical strategy combining QuEChERS extraction with low-temperature partitioning (LTP) for the determination of multiclass pesticide residues in cocoa beans by GC–MS. Extraction conditions were optimized using a fractional factorial design, resulting in a simple and efficient workflow suitable for complex cocoa matrices.The validated method showed satisfactory limits of detection and quantification, recoveries within 70–120%, and good overall performance. Application to cocoa samples from Brazil detected permethrin in several samples, demonstrating that the QuEChERS–LTP approach is an effective and reliable cleanup strategy for routine pesticide residue analysis in cocoa.<blockquote><h4>The original article</h4><h4><a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c10360">QuEChERS Combined with Low-Temperature Partitioning and GC–MS as an Analytical Strategy for the Determination of Multiclass Pesticide Residues in Cocoa Beans</a></h4>Priscilla M. de Freitas Machado, Madson M. Nascimento, Paulo R. R. Mesquita, Manuela B. Nascimento, Lilian Lefol N. Guarieiro, Gisele O. da Rocha, Jailson B. de Andrade, Raildo M. de Jesus*ACS Omega 2025, 10, 51, 63464–63473<a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1021/acsomega.5c10360">https://doi.org/10.1021/acsomega.5c10360</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.Cocoa is best known as the primary raw material for chocolate but is also processed into products such as cocoa butter, biscuits, cocoa honey, and cocoa powder. Cocoa powder is derived from roasted, pressed, and milled nibs, containing on average 20% (w/w) lipids on a dry basis and less than 9% moisture. <a href="javascript:void(0);">(3,4)</a>According to the Brazilian Health Regulatory Agency (ANVISA), pesticides such as atrazine, bifenthrin, cyproconazole, metalaxyl, tebuconazole, trifloxystrobin, and permethrin are approved for use in Brazil. <a href="javascript:void(0);">(13)</a> However, among these, only metalaxyl, trifloxystrobin, and tebuconazole are authorized by the European Union. <a href="javascript:void(0);">(14)</a> Thus, investigating these contaminants in cocoa samples is of utmost importance, as Brazil is one of the largest cocoa exporters, supplying cocoa commodities to South America, the United States, and the European Union. <a href="javascript:void(0);">(2)</a> Furthermore, Organochlorine pesticides, in particular, belong to the class of persistent organic pollutants (POPs). Although banned in many countries, they continue to be used in some developing nations because of their chemical stability, resistance to degradation, volatility, and high lipophilicity, which promote bioaccumulation and neurotoxicity. <a href="javascript:void(0);">(15)</a> Epidemiological evidence also associates their exposure with Parkinson’s disease, certain cancers, diabetes, and endometriosis. <a href="javascript:void(0);">(16)</a>Residues of pesticides in cocoa have been reported in various studies. <a href="javascript:void(0);">(17)</a> Analyzing pesticide residues in cocoa presents analytical challenges due to the matrix’s complexity, comprising high lipid content, fatty acids and esters, sugars, polyphenols, and caffeine. These components can interfere with extraction efficiency and contaminate analytical instrumentation. <a href="javascript:void(0);">(18)</a> Therefore, efficient sample preparation methods incorporating effective cleanup steps are essential for accurate residue determination.Several techniques have been employed for multiresidue pesticide analysis in cocoa. For instance, Idowu et al. <a href="javascript:void(0);">(19)</a> quantified 14 organochlorines using Soxhlet extraction and silica/Na2SO4 cleanup, with GC ECD detection. Okoffo et al. <a href="javascript:void(0);">(20)</a> determined 13 organophosphates and 9 pyrethroids employing SPE cartridges (Envi-carb/LC-NH2 and Bond Elute C18), acetonitrile extraction, and GC PFPD or GC ECD quantification. Yusiasih et al. <a href="javascript:void(0);">(21)</a> applied dispersive SPE with PSA, Florisil, and MgSO4 for pyrethroids, followed by GC ECD and GC–MS.Therefore, this study aimed to evaluate the effectiveness of a QuEChERS–LTP analytical procedure for the determination of multiclass pesticide residues in cocoa beans. The factors that affect the QuEChERS–LTP procedure efficiency were optimized. After validation, the procedure was employed to investigate the occurrence of 15 multiclass pesticides in cocoa samples.<h4>Experimental Section</h4><h5>Instrumental Apparatus</h5>Pesticide separation and identification were performed on a Shimadzu <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=1&amp;search=GC-MS-QP2010SE">GC-MS-QP2010SE</a> system (Kyoto, Japan) equipped with an <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=1&amp;search=AOC-20i">AOC-20i autosampler</a>. Separation was achieved using an <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=DB-5MS">Agilent DB-5MS capillary column</a> (30 m × 0.25 mm × 0.25 μm) with a stationary phase of 5% phenyl/95% dimethylpolysiloxane. The instrumental conditions were based on Nascimento et al. <a href="javascript:void(0);">(49)</a> and they are summarized in <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c10360#tbl4">Table 4</a>.For quantification, the base peak was used, while two additional ions were monitored for confirmation (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acsomega.5c10360/suppl_file/ao5c10360_si_001.pdf">Table S2</a>) in accordance with SANTE guidelines. <a href="javascript:void(0);">(50)</a> A GC–MS/SIM chromatogram illustrating the separation of all target pesticides is presented in <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c10360#fig5">Figure 5</a>.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/ACS_Omega_2025_10_51_63464_63473_Figure_5_Extracted_ion_chromatogram_EIC_in_SIM_mode_of_the_target_pesticides_f2461c14f4.jpg" alt="ACS Omega 2025, 10, 51, 63464–63473: Figure 5. Extracted ion chromatogram (EIC) in SIM mode of the target pesticides obtained from the injection of a mixed standard solution at 100 μg L–1. Analytes are listed in order of elution: [1] Molinate (6.18 min); [2] α-HCH (8.15 min); [3] atrazine-d5 (8.69 min); [4] atrazine (8.75 min); [5] diazinon (9.31 min); [6] disulfoton (9.67 min); [7] dimethachlor (10.60 min); [8] metalaxyl (11.25 min); [9] p,p′-DDE (15.82 min); [10] cyproconazole I (16.50 min); [11] cyproconazole II (16.56 min); [12] p,p′-DDD (17.29 min); [13] ethion (17.34 min); [14] trifloxystrobin (18.43 min); [15] tebuconazole (19.13 min); [16] bifenthrin (20.47 min); [17] permethrin I (23.92 min); [18] permethrin II (24.18 min)." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_ACS_Omega_2025_10_51_63464_63473_Figure_5_Extracted_ion_chromatogram_EIC_in_SIM_mode_of_the_target_pesticides_f2461c14f4.jpg 245w," sizes="100vw" width="2080" height="835"><h5>Application of the Proposed Procedure to Real Samples</h5>In a 50 mL Falcon tube, 2.0 g of sample was weighed using an analytical balance (AUX320, Shimadzu, Kyoto, Japan). A total of 2.0 g of salt (NaCl and Na2SO4 in a 1:1 w/w ratio) was added, followed by an aliquot of the atrazine-d5 solution (surrogate standard) to yield a final concentration of 250 μg kg–1. A mixture of acetonitrile (8.0 mL) and ultrapure water (2.0 mL) was then added. The system was vortexed (K40-10208, Kasvi, São Paulo, Brazil) for 3.0 min at 2500 rpm and centrifuged (MPW-351R, MPW Med. Instruments, Warsaw, Poland) for 10.0 min at 15 °C and 10,000 rpm. After phase separation, approximately 6.0 mL of the supernatant was transferred to a Falcon tube containing 150.0 mg of PSA sorbent. The mixture was vortexed again for 3.0 min at 2500 rpm and centrifuged for an additional 10.0 min under the same conditions. The tubes were then placed in the freezer for 24 h. Once the aqueous phase had frozen, the organic extract containing the analytes was collected, filtered through a Cytiva Whatman MiniUniprep G2 vial with a 0.20 μm membrane filter (Marlborough, Massachusetts, USA), and injected into the GC–MS system (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c10360#fig6">Figure 6</a>).<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/ACS_Omega_2025_10_51_63464_63473_Figure_6_Schematic_representation_of_the_extraction_procedure_using_the_Qu_E_Ch_ERS_LTP_procedure_for_pesticide_extraction_in_cocoa_powder_samples_ed58549bcf.jpg" alt="ACS Omega 2025, 10, 51, 63464–63473: Figure 6. Schematic representation of the extraction procedure using the QuEChERS–LTP procedure for pesticide extraction in cocoa powder samples." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_ACS_Omega_2025_10_51_63464_63473_Figure_6_Schematic_representation_of_the_extraction_procedure_using_the_Qu_E_Ch_ERS_LTP_procedure_for_pesticide_extraction_in_cocoa_powder_samples_ed58549bcf.jpg 223w," sizes="100vw" width="1458" height="1022"><h4>Results and Discussion</h4><h5>Evaluation of the Effect of Low and Ultralow Temperatures on the Analytical Response</h5>Studies reporting the use of LTP generally employ a conventional freezer, which typically reaches −18 ± 2 °C as the minimum temperature. In this equipment, effective phase separation can require 8 to 24 h. <a href="javascript:void(0);">(35−37)</a> In contrast, ultralow temperature freezers (ultrafreezers) can reach −80 °C, leading to a substantial reduction in partitioning time. In this study, tests performed with the conventional freezer achieved satisfactory partitioning after 24 h, whereas in the ultrafreezer, complete partitioning was observed in only 20 min.Considering the analytical response in terms of peak area (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c10360#fig3">Figure 3</a>), higher signals were obtained when LTP was performed in a conventional freezer rather than an ultrafreezer. This behavior can be attributed to the partitioning mechanism. <a href="javascript:void(0);">(32)</a> Partitioning depends on cooling and the subsequent freezing of the aqueous phase. In the conventional freezer, the slower freezing rate provides sufficient time for the system to approach thermodynamic equilibrium, favoring analyte diffusion between phases. Under these conditions, analyte molecules have more time to migrate and distribute optimally before complete solidification. In contrast, the rapid freezing in the ultrafreezer may trap analytes in a nonideal distribution, reducing the efficiency of the partitioning process <a href="javascript:void(0);">(32)</a> (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c10360#fig3">Figure 3</a>). According to these observations, the conventional freezer was selected for subsequent experiments.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/ACS_Omega_2025_10_51_63464_63473_Figure_3_Comparison_of_chromatographic_peak_areas_of_pesticides_after_partitioning_in_the_conventional_freezer_versus_the_ultrafreezer_9598bcfec3.jpg" alt="ACS Omega 2025, 10, 51, 63464–63473: Figure 3. Comparison of chromatographic peak areas of pesticides after partitioning in the conventional freezer versus the ultrafreezer." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_ACS_Omega_2025_10_51_63464_63473_Figure_3_Comparison_of_chromatographic_peak_areas_of_pesticides_after_partitioning_in_the_conventional_freezer_versus_the_ultrafreezer_9598bcfec3.jpg 175w," sizes="100vw" width="996" height="891"><h5>Application to Real Samples</h5>Fifteen samples were analyzed in triplicate, comprising two from the State of Pará and 12 from the State of Bahia, located in the North and Northeast regions of Brazil, respectively. Among the 15 pesticides investigated, only permethrin isomers were quantified in four samples (<a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c10360#tbl3">Table 3</a>). The herbicide molinate was also detected in three samples; however, its concentration was below LOQ. Permethrin isomers concentrations ranged from 17.1 ± 0.3 to 49.6 ± 1.8 μg kg–1. These values are below the MRL established by European Union regulation, which is 100 μg kg–1. <a href="javascript:void(0);">(42)</a> Although permethrin is not permitted in the European Union, <a href="javascript:void(0);">(42)</a> it remains authorized for use as insecticide in Brazil, particularly in crops such as cotton, rice, coffee, citrus, cabbage, beans, tobacco, maize, soybean, tomato, wheat, and grape. <a href="javascript:void(0);">(13)</a> However, no MRL values have been established for cocoa beans under Brazilian legislation. <a href="javascript:void(0);">(13)</a> <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c10360#tbl3">Table 3</a> shows the concentration of detected compounds in the cocoa samples.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/ACS_Omega_2025_10_51_63464_63473_Table_3_Mean_Concentrations_mg_kg_1_Standard_Deviation_of_Target_Pesticides_Detected_in_This_Study_2427955699.jpg" alt="ACS Omega 2025, 10, 51, 63464–63473: Table 3. Mean Concentrations (μg kg–1 ± Standard Deviation) of Target Pesticides Detected in This Study" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_ACS_Omega_2025_10_51_63464_63473_Table_3_Mean_Concentrations_mg_kg_1_Standard_Deviation_of_Target_Pesticides_Detected_in_This_Study_2427955699.jpg 196w," sizes="100vw" width="1070" height="851">To assess method performance for pesticides not detected in the cocoa samples, one of the analyzed samples was fortified with a mixed standard solution at concentrations of 50, 250, and 500 μg kg–1. The fortified analytes were subsequently detected in the chromatograms presented in <a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/suppl/10.1021/acsomega.5c10360/suppl_file/ao5c10360_si_001.pdf">Figures S2–S4</a>, indicating good response of the proposed method.<h4>Conclusions</h4>The QuEChERS–LTP procedure was successfully developed for the determination of 16 multiclass pesticide residues in cocoa beans. For the first time, ultralow temperature (−80 °C) was applied to accelerate the low-temperature partitioning process during pesticide extraction from cocoa beans. Nevertheless, conventional freezing at −12 °C proved to be more effective for the extraction of the target analytes.Evaluation of the matrix effect demonstrated that matrix-matched analytical curves, constructed in an analyte-free cocoa bean extract, were more effective in compensating for matrix interferences than the use of analyte protectants.The pyrethroid permethrin was quantified in four cocoa samples. However, the concentrations did not exceed the MRL established by European Union legislation.Overall, the QuEChERS–LTP procedure proved to be a promising approach for pesticide residue determination, as it requires smaller volumes of solvents and reagents, involves fewer cleanup and extraction steps, and shows strong potential for application to other complex matrices.

QuEChERS Combined with Low-Temperature Partitioning and GC–MS as an Analytical Strategy for the Determination of Multiclass Pesticide Residues in Cocoa Beans

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The Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences (IOCB Prague) is a leading scientific institution in the Czech Republic, recognized internationally. Its primary mission is basic research in the fields of chemical biology and medicinal chemistry, organic and material oriented chemistry, chemistry of natural compounds, biochemistry and molecular biology, physical chemistry, theoretical chemistry, and analytical chemistry. 

Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences

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Wasson Pressurized Liquid Auto-sampler (LS100B)

Wasson-ECE Liquid Auto-Sampler (LS100B) offers laboratory automation for pressurized liquid samples such as liquefied petroleum gas (LPG) and natural gas liquids (NGL).

Wasson-ECE Liquid Auto-Sampler (LS100B) offers laboratory automation for pressurized liquid samples such as liquefied petroleum gas (LPG) and natural gas liquids (NGL).
The LS100B uses inert gases to maintain pressure so that the sample remains in the liquid state at ambient temperature as it passes to the GC for analysis.
The LS100B accommodates up to nine sample cylinders with 1/4 inch tube, VCO, or quick connect fittings. These fittings hold the sample cylinders vertically, ensuring that samples are drawn from the bottom of the cylinder.
<h4>Pressurized Liquid Auto-sampler Features</h4>
<ul>
<li>Purges automatically with carrier gas between each sample run
</li>
<li>Remote-starts the GC and the data recording software such as ChemStation™
</li>
<li>Adds a date/time stamp to all samples
</li>
<li>Holds up to nine 3.5 inch / 8.9 cm diameter sample cylinders
</li>
<li>Works with standard open or floating-piston sample cylinders
</li>
<li>Pauses automatically when it detects that the GC is not running or not ready
</li>
<li>Can interrupt the scheduled sample sequence to process a priority sample
</li>
</ul>

Wasson Dynamic Blender for GC (DB302)

The Dynamic Blender is a portable gas blending device that dilutes a sample or a certified standard with a matrix gas of choice.

Gas chromatography (GC) analyses often include trace level detection of components requiring samples or standards at low concentrations. Some analytes are expensive or difficult to purchase at low levels due to reactivity, adsorption, or high molecular weight. Analyses may also cover a wide concentration range, requiring multi-point calibration.
The Wasson-ECE Dynamic Blender (DB302) provides a simple solution to these calibration needs. The Dynamic Blender is a portable gas blending device that dilutes a sample or a certified standard with a matrix gas of choice. One certified standard with concentrations at the upper limit of the desired calibration curve can be diluted to a lower level (&gt;2 orders of magnitude lower) to create a full calibration curve.
An inert flow path and heated bridge eliminate adsorption and condensation problems when blending gas standards that include sulfur, nitrogen, and other reactive compounds.
An on-board flow controller allows the diluent gas flow to be controlled digitally and samples are fed directly to a gas chromatograph. The Dynamic Blender eliminates the need to purchase and store multiple gas cylinders and provides an easy, cost-effective solution for gas phase calibration needs.
<h4>Dynamic Blender Features</h4>
<ul>
<li>Approximately 100 pre-programmed pure diluent gases and mixtures and twenty user configurable diluent mixture slots.
</li>
<li>Maximum Diluent Pressure of 100 psi (leak tested to this pressure)
</li>
<li>Maximum Temperature of 150°C (operation verified at this temp.)
</li>
<li>Mass Flow Controller Range of 10 – 500 cc/min
</li>
<li>7 μm in-line gas filters (treated) are also provided
</li>
<li>Specially passivated tubing for trace reactive compounds (sulfurs, oxygenates, etc.)
</li>
</ul>
*This treatment is not suitable for samples with pH &gt; 8.0, so please notify your sales representative if you have high pH samples.

Wasson Variable Pressure Sampler (VPS)

The Variable Pressure Sampler (VPS) works in two ways to ensure the precision and accuracy of gas results.

The Variable Pressure Sampler (VPS) works in two ways to ensure the precision and accuracy of gas results. The first method is pressure correction, used to create uniform pressure among all injected samples and the calibration blend. The second method is multi-point calibration, which can deliver a calibration blend to the GC at various pressures.
The VPS pressure correction system performs a multi-step process that ensures samples and calibration blends are at uniform pressures when they are injected.
First, when the calibration blend is run through the GC, the VPS measures and stores the pressure of the calibration blend at the time of injection. Then, as each sample is injected at the stored pressure, the VPS adjusts the pressure of the sample to match the pressure of the calibration blend.
The inject pressure of the sample is reported to Agilent Technologies OpenLAB ChemStation software so calculations and quality control operations can be performed.
Using the VPS, calibration samples can be run at various pressures from a single standard. This decreases overall lab costs while ensuring greater accuracy in results. The multi-point calibration function allows testing for signal linearity at different pressures. With this feature, the user can easily pinpoint the range of pressures which generates the most accurate and meaningful results from the calibration standard.
<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Wassson_Variable_Pressure_Sampler_VPS_linearity_77314725d6.jpg" alt="Wassson: Variable Pressure Sampler (VPS) - linearity"/>

Wasson LPG Vaporizer (1107)

The LPG Vaporizer uses an innovative, proprietary technique to vaporize liquid samples for injection in an existing GC system.

The LPG Vaporizer uses an innovative, proprietary technique to vaporize liquid samples for injection in an existing GC system. This convenient laboratory system offers flexibility and accuracy for both gas and liquid samples.
The LPG Vaporizer is more convenient than a typical liquid sample valve with more accurate results. All liquid samples are vaporized and run at a constant pressure, eliminating sample density changes that cause errors in liquid phase samples. This ensures sharp, easy-to-read peaks for all samples.
The LPG Vaporizer is built with specially passivated parts for analyzing trace reactive analytes such as sulfurs and oxygenates.
Wasson-ECE&#39;s unique, proprietary vaporization technique produces an even and accurate gas sample. Other vaporizers use tubing with a large volume, causing samples to fractionate when vaporized. This can lead to incomplete sample analysis. The LPG Vaporizer controls the injection volume so that all elements in the liquid sample are vaporized and sent to the GC simultaneously, producing a complete and accurate analysis of the sample.
<h4>LPG Vaporizer Features</h4>
<ul>
<li>Inject liquid and gas samples with a single valve
</li>
<li>High sample throughput
</li>
<li>Purging technique reduces cross-contamination
</li>
<li>Ability to stop sample flow to the GC at any time
</li>
<li>Controlled injection volume
</li>
<li>4 ft. heated bridge from vaporizer to customer&#39;s GC sample valve to prevent sample re-condensing
</li>
</ul>

Wasson Gas Auto-sampler (AS202)

The Gas Auto-sampler (AS202) is a stand-alone device that delivers samples to the GC through a heated bridge, ensuring that samples are injected at the appropriate temperature.

The Gas Auto-sampler (AS202) is a stand-alone device that delivers samples to the GC through a heated bridge, ensuring that samples are injected at the appropriate temperature. The heated pathway is purged with carrier gas between each sample injection, and a vacuum pump ensures an extremely low level of matrix cross-contamination (typically less than 50 ppm).
Samples are loaded into the AS202 oven, which can hold up to twelve 500cc sample cylinders or nine 1L cylinders. The shelves are removable and adjustable and can also be tilted to prevent injection of any residual liquids which then changes the setup to allow for a maximum of eight 500cc or six 1L cylinders.
Samples (1000 psig / 6895 kPa max) are automatically regulated during the purging sequence so the GC injects all samples and calibration blends at atmospheric pressure. The AS202 can also be configured to automate injection of samples that are already at atmospheric pressure.
The table below compares the GC analysis results for 2 mL samples of n-pentane and n-hexane at 100 psig in propane. In the first trial, the sample is sent to the GC from the AS202 at ambient temperature; in the second trial the AS202 heats the samples to 130°C before injection.
<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Wasson_Wasson_autosampler_pro_plynne_vzorky_Srovnani_vysledku_GC_analyz_f7c0ad0991.jpg" alt="Wasson: Repeatability Comparisons - Heated vs. Unheated"/>

Watrex VICI Consumables for HPLC/GC

As an authorized distributor of VICI, we provide a wide range of high-quality chromatography consumables that meet the most demanding requirements for precision and reliability.

As an authorized distributor of VICI, we provide a wide range of high-quality chromatography consumables that meet the most demanding requirements for precision and reliability.Our offer includes injection valves, adapters, tubing, filters, columns and other products that optimize the performance of your HPLC systems. Thanks to our close cooperation with partners, we guarantee the latest technology and expert advice.Explore our range using the catalogs from<a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/Watrex_VICI_V_ddafed74a8.pdf"> VICI Valco</a> and <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/Watrex_VICI_J_c72f706329.pdf">VICI Jour</a> and do not hesitate to contact us for a non-binding quote at watrex@watrex.com or visit our website <a target="_blank" rel="noopener noreferrer" href="https://watrex.com/cs/uvod/?utm_source=labrulez">www.watrex.com</a>.<h3>VICI Valco Instuments</h3>For over 50 years, VICI Valco Instruments Co. Inc. has been the leading designer and manufacturer of standard and custom valves and fittings for precision analytical, biomedical, and biocompatible instrumentation.<h4>The offer includes, for example:</h4><ul><li>Injectors and valves</li><li>Fittings</li><li>Detectors</li><li>Valve actuation and accessories</li></ul>Vici Valco product line also includes a wide range of related products such as pneumatic and electric actuators, tubing and sampling loops, heated enclosures, valve sequence and temperature controllers, gas purifiers, GC detectors, and digital interfaces.<h3>VICI Jour</h3>VICI Jour offer the complete Jour line of accessories and consumables for fluid transfer in HPLC and LC.<h4>The offer includes, for example:</h4><ul><li>Tubing (PEEK, F-polymeric, stainless steel)</li><li>Fittings (high pressure and low pressure)</li><li>Filters (high pressure and low pressure) and frits</li><li>Safety products</li><li>PEEK columns and guard columns</li><li>Tools and LC accessories</li></ul>Jour products include a complete line of tubing and capillaries in a wide variety of diameters and materials, high and low pressure fingertight fittings and connection accessories, column hardware, high and low pressure filters, cutters and other tools, solvent saver, safey caps, waste caps, backpressure regulators, and much more.

EST Analytical AS120 Autosampler

The AS120 GC Autosampler boosts productivity with dual-injector support, 120/200 vial capacity, programmable injections, and seamless GC/GC-MS integration.

The AS120 Autosampler is a cost-effective, fully electric XYZ sampler for GC and GC/MS applications. Driven by stepper motor technology, it combines modern engineering with user-friendly operation, meeting both routine and advanced analytical needs. With high-capacity sample trays, flexible injection modes, and reliable performance, the AS120 ensures laboratories can boost productivity while maintaining precise, consistent results.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/EST_Analytical_AS_120_Autosampler_7cc5a79884.jpg" alt="EST Analytical: AS120 Autosampler" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_EST_Analytical_AS_120_Autosampler_7cc5a79884.jpg 203w," sizes="100vw" width="1056" height="812"><h4>Key Features</h4><h5>Maximum Productivity</h5><ul><li>Dual-injector capability for maximum GC throughput</li><li>Automated injector alignment—no manual adjustments required</li><li>Variable injection rate tailored to injector type and analytical method</li><li>Choice of 120- or 200-position sample trays, easily removable for quick loading</li></ul><h5>Durable, Flexible Engineering</h5><ul><li>Robust XYZ syringe mechanism accesses vials, solvents, and standards with precision</li><li>Adjustable parameters: injection volume, speed, dwell times, and solvent flush options</li><li>Supports multiple methods per sequence and dual-column operation</li><li>Fully programmable via intuitive keypad interface</li></ul><h5>Hassle-Free Operation</h5><ul><li>Compatible with screw-cap and crimp-top septum vials</li><li>Simple GC integration with standard remote I/O signals and RS-232 communication</li><li>Quick mounting with keypad-based syringe/injector alignment</li><li>Priority manual sample feature enables urgent “RUSH” sample handling</li></ul><h4>Technical Specifications</h4><ul><li>Drive: All-electric, stepper motor XYZ system</li><li>Capacity: 120 or 200 vial tray options</li><li>Compatibility: GC and GC/MS systems with standard I/O and RS-232 interface</li><li>Injection Modes: Variable rate, programmable volume, dual-injector support</li><li>Control: Keypad-driven menu with multiple method programming</li><li>Sample Handling: Screw-cap or crimp-top septum vials</li></ul>

EST Analytical FLEX 2 Robotic Sampling Platform

The FLEX 2 autosampler streamlines GC/GC-MS workflows with liquid, headspace, and SPME capability, MTX tool change, and Prep Ahead for faster, more reliable VOC analysis.

The FLEX 2 is a versatile GC autosampler designed to handle both sample preparation and sample introduction for GC and GC/MS analysis. Supporting liquid injection, headspace, and SPME, it delivers exceptional accuracy and reproducibility. Its Prep Ahead function improves efficiency by allowing sample preparation during ongoing GC runs, maximizing system utilization and throughput.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/EST_Analytical_FLEX_2_Robotic_Sampling_Platform_3_853e02f151.jpg" alt="EST Analytical: FLEX 2 Robotic Sampling Platform" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_EST_Analytical_FLEX_2_Robotic_Sampling_Platform_3_853e02f151.jpg 168w," sizes="100vw" width="628" height="584"><h4>Key Features</h4><h5>Flexible Sample Preparation with Multi Tool Change (MTX)</h5><ul><li>Automated Multi Tool Change (MTX) enables seamless switching between tools</li><li>Enhances laboratory productivity, accuracy, and safety by reducing manual prep errors</li><li>Supports dilution, reagent addition, and internal standard spiking with precision</li><li>Can operate as a benchtop preparation station for derivatization and extraction steps</li></ul><h5>Liquid Injection Capabilities</h5><ul><li>Injection range: 0.5–10 μL (standard syringe) or 50–500 μL (optional large-volume syringe)</li><li>Supports both standard and large-volume injections (up to 500 μL)</li><li>Programmable injection speed control, from ultra-fast to very slow</li><li>Optional cooled trays available for temperature-sensitive samples</li></ul><h5>Headspace Sampling</h5><ul><li>Injection range: 100–2500 μL (2.5 mL syringe), 100–1000 μL (1.0 mL syringe), or 500–5000 μL (5.0 mL syringe)</li><li>Offers both orbital and oscillating agitation to improve sample consistency</li><li>Six heated vial positions for 2, 10, or 20 mL vials</li><li>Temperature range: ambient to 200 °C</li><li>Shaking: orbital (120–750 rpm) or oscillation (190 Hz)</li></ul><h5>Automated SPME</h5><ul><li>Compatible with both traditional and direct immersion SPME methods</li><li>Heated conditioning station:<ul><li>Fiber: ambient to 350 °C</li><li>Needle: ambient to 150 °C</li><li>Sweep gas port for conditioning</li></ul></li><li>Heated mixing station: ambient to 150 °C, mixing speeds 380–725 rpm</li></ul><h5>Efficiency &amp; Throughput</h5><ul><li>Prep Ahead function allows ongoing sample prep during GC runs</li><li>Fully automates switching between liquid injection, headspace, and SPME with MTX</li><li>Reduces manual workload and preparation errors while improving reproducibility</li></ul><h4>Technical Specifications</h4><ul><li>Compatible Systems: GC and GC/MS platforms</li><li>Injection Modes: Liquid (0.5–500 μL), Headspace (100–5000 μL), SPME (traditional &amp; direct immersion)</li><li>Temperature Ranges: Headspace up to 200 °C, SPME fiber up to 350 °C, SPME needle up to 150 °C</li><li>Agitation: Orbital (120–750 rpm) and oscillating (190 Hz)</li><li>Capacity: Six heated vial positions for 2, 10, or 20 mL vials</li><li>Automation: Multi Tool Change (MTX), Prep Ahead function</li></ul>

EST Analytical LGX-50 for Methane in Water

The EST LGX-50 automates RSK-175 dissolved gas testing in water, boosting throughput, ensuring ASTM/EPA compliance, and reducing manual sample preparation errors.

The LGX-50 automates the preparation of water samples for headspace analysis of dissolved gases such as methane, ethane, and ethene. Traditionally, RSK-175 testing has been labor-intensive and time-consuming, requiring manual vial preparation. The LGX-50 eliminates this step, streamlining workflows and ensuring compliance with EPA Method 5035 and ASTM D8028. By automating dissolved gas extraction, laboratories can boost throughput, reduce errors, and deliver more consistent results for shale gas and environmental testing.<h4>Key Features</h4><h5>Maximized Productivity</h5><ul><li>Fully automates RSK-175 sample processing</li><li>ASTM D8028 compliant for dissolved gas testing</li><li>Holds up to 50 samples for high-throughput operation</li><li>Optical sensors prevent vial misplacement and syringe/elevator errors</li><li>Robust XYZ design ensures reliability and consistent performance</li></ul><h5>Simplified Operation</h5><ul><li>Intuitive, user-friendly software designed for quick setup and operation</li><li>Remote access functionality allows labs to monitor sample progress via the server</li><li>Reduces manual preparation steps, increasing accuracy and reproducibility</li></ul><h4>Technical Specifications</h4><ul><li>Compliance: EPA Method 5035, ASTM D8028</li><li>Capacity: Up to 50 samples per batch</li><li>Target Compounds: Methane, ethane, ethene, and other dissolved gases in water</li><li>Automation: XYZ robotic design with optical sensors for error prevention</li><li>Software: Intuitive, remote-access capable interface</li></ul>

VUV Analytics VGA-100 Gas Chromatography Detector for TRACE 1600 Series GC

The VGA-100 GC detector with VUV technology and TRACE 1600 GC delivers rapid, accurate analysis of isomers and complex mixtures with higher productivity and reliability.

The Thermo Scientific™ VGA-100™ Gas Chromatography Detector (developed by VUV Analytics, Inc.) introduces the next generation of GC detection through revolutionary vacuum ultraviolet (VUV) absorption technology. Delivering unmatched sensitivity, selectivity, and precision, the VGA-100 provides both qualitative and quantitative data with exceptional accuracy.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Thermo_Scientific_VGA_100_Gas_Chromatography_Detector_2_e45d1cf5c3.jpg" alt="Thermo Scientific VGA-100 Gas Chromatography Detector." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Thermo_Scientific_VGA_100_Gas_Chromatography_Detector_2_e45d1cf5c3.jpg 165w," sizes="100vw" width="752" height="710"><h3>Key Benefits</h3><ul><li>Seamless integration with TRACE 1600 Series GC – Together, the VGA-100 and<a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/products/483"> TRACE™ 1600 GC </a>form a powerful, scalable, and intuitive system designed to meet the most demanding laboratory workflows.</li><li>Enhanced productivity and speed – Faster analysis, higher throughput, and reduced operational costs thanks to automated spectral deconvolution and streamlined data processing.</li><li>Superior selectivity and clarity – Compound-specific absorption spectra enable confident identification of isomers and co-eluting compounds without baseline separation.</li><li>Universal and mass-sensitive detection – Provides comprehensive 3D data (time, wavelength, intensity) with library matching for reliable compound identification across a broad range of analytes.</li><li>Ease of use – No vacuum pumps required, minimal maintenance, intuitive operation, and full compatibility with both R&amp;D and QC environments.</li><li>VUV Analyze™ Software integration – Push-button workflows, automated Time Internal Deconvolution™ (TID), and ready-to-use spectral libraries deliver fast, reliable, and reproducible results.</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Thermo_Scientific_VGA_100_Gas_Chromatography_Detector_5_e387eb9360.jpg" alt="Thermo Scientific VGA-100 Gas Chromatography Detector: VUV spectra of hydrocarbons exhibit class-based similarities, simplifying complex fuel mixture analysis." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Thermo_Scientific_VGA_100_Gas_Chromatography_Detector_5_e387eb9360.jpg 245w," sizes="100vw" width="1170" height="552"><h3>Applications</h3>The VGA-100 detector addresses critical analytical challenges such as accurate isomer identification, analyte co-elution, long run times, and complex data interpretation. It is especially impactful in:<ul><li>Petrochemical analysis – Simplifies PIONA (paraffins, isoparaffins, olefins, naphthenes, aromatics) characterization in finished fuels, enabling rapid, automated fuel analysis.</li><li>Environmental, food, and pharmaceutical testing – Reliable quantification of complex mixtures with improved accuracy and reduced calibration complexity.</li><li>Quality control and research labs – Scalable, intuitive platform supporting compliance, throughput, and robust data integrity.</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Thermo_Scientific_VGA_100_Gas_Chromatography_Detector_3_ddcbe84bde.jpg" alt="Thermo Scientific VGA-100 Gas Chromatography Detector: Simplified PIONA compound analysis in finished gasoline." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Thermo_Scientific_VGA_100_Gas_Chromatography_Detector_3_ddcbe84bde.jpg 245w," sizes="100vw" width="956" height="426"><h3>Summary</h3>The VGA-100 GC Detector sets a new benchmark in gas chromatography by combining VUV absorption technology with the robust performance of the TRACE 1600 Series GC. Laboratories gain a powerful “ready-to-use” solution that enhances throughput, accuracy, and confidence across diverse industries.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Thermo_Scientific_VGA_100_Gas_Chromatography_Detector_4_5595ee9da1.jpg" alt="Thermo Scientific VGA-100 Gas Chromatography Detector." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Thermo_Scientific_VGA_100_Gas_Chromatography_Detector_4_5595ee9da1.jpg 139w," sizes="100vw" width="816" height="918">

Products focused on GC - page 3

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