<p><strong>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 </strong><i><strong>Nature Chemical Biology</strong></i><strong>.</strong></p><p><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"></p><div><p>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.</p><p>In their study,<strong> </strong><a target="_blank" rel="noopener noreferrer" href="https://cahova.group.uochb.cz/en"><strong>Dr. Hana Cahová</strong></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.</p><p>The work was significantly shaped by <strong>Valentina Serianni from Hana Cahová’s team</strong>, who demonstrated the ability of dinucleoside polyphosphates to initiate gene transcription, and by <strong>Jana Škerlová</strong>, 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.</p><p>Hana Cahová adds: <i>“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.”</i></p><p><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"></p><div><p>Cryogenic electron microscopy (cryo-EM) was central to the project. This part of the work was led by<strong> Dr. Tomáš Kouba</strong>, one of the authors of the study. <i>“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,”</i> he explains.</p><p>Last year, IOCB Prague opened a new <a target="_blank" rel="noopener noreferrer" href="https://cryoem.group.uochb.cz/en"><strong>cryo-EM center</strong></a><strong> </strong>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.</p><p><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"></p><blockquote><h4><strong>The Original article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://www.nature.com/articles/s41589-025-02134-5"><strong>Molecular insight into 5′ RNA capping with Np<sub>n</sub>Ns by bacterial RNA polymerase</strong></a></h4><p>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;</p><p>Nat. Chem. Biol. 21 (2026)</p><p><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></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><h4><strong>Abstract</strong></h4><p>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 <i>Thermus</i> <i>thermophilus</i>. 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.</p></div></div>

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

<p><strong>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.</strong></p><blockquote><h4><a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/webinars"><strong>👉 DETAILS AND REGISTRATION IN THE WEBINARS SECTION</strong></a></h4><p><strong>👉 Search and filter in the largest global database</strong> with over <strong>5 000 GC, LC, MS and spectroscopy webinars</strong>.</p></blockquote><div><div><div><div><div><div><h5><strong>1. Thermo Fisher Scientific: Process Raman – A Reliable and Versatile Tool for Downstream Process Monitoring and Control for mAb Production</strong></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><p>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.</p><h5><strong>2. Wasson-ECE Instrumentation: The Data Driven Plant – How AI Transforms Chemical Manufacturing</strong></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><p>Explore how artificial intelligence is applied to improve process efficiency, monitoring, and decision-making in modern chemical manufacturing.</p><h5><strong>3. New Food Magazine: The Science of Next-Gen Ingredients – Fermentation, Formulation and Function</strong></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><p>Discover how fermentation-driven innovation is transforming functional food ingredients, with analytical insights to optimize flavour, functionality, and product stability.</p></div></div></div></div></div></div>

Webinars LabRulezGCMS Week 07/2026

<p><strong>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.</strong></p><p>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.</p><blockquote><h4><strong>The original article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://pubs.acs.org/doi/10.1021/acsomega.5c10360"><strong>QuEChERS Combined with Low-Temperature Partitioning and GC–MS as an Analytical Strategy for the Determination of Multiclass Pesticide Residues in Cocoa Beans</strong></a></h4><p>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*</p><p>ACS Omega 2025, 10, 51, 63464–63473</p><p><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1021/acsomega.5c10360">https://doi.org/10.1021/acsomega.5c10360</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><p>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></p><p>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></p><p>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.</p><p>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/Na<sub>2</sub>SO<sub>4</sub> 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-NH<sub>2</sub> 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 MgSO<sub>4</sub> for pyrethroids, followed by GC ECD and GC–MS.</p><p>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.</p><h4><strong>Experimental Section</strong></h4><h5><strong>Instrumental Apparatus</strong></h5><p>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"><strong>GC-MS-QP2010SE</strong></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"><strong>AOC-20i autosampler</strong></a>. Separation was achieved using an <a target="_blank" rel="noopener noreferrer" href="https://gcms.labrulez.com/library?mainauthorItems=10&amp;search=DB-5MS"><strong>Agilent DB-5MS capillary column</strong></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>.</p><p>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>.</p><p><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"></p><h5><strong>Application of the Proposed Procedure to Real Samples</strong></h5><p>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 Na<sub>2</sub>SO<sub>4</sub> in a 1:1 w/w ratio) was added, followed by an aliquot of the atrazine-<i>d</i><sub>5</sub> solution (surrogate standard) to yield a final concentration of 250 μg kg<sup>–1</sup>. 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>).</p><p><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"></p><h4><strong>Results and Discussion</strong></h4><h5><strong>Evaluation of the Effect of Low and Ultralow Temperatures on the Analytical Response</strong></h5><p>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.</p><p>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.</p><p><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"></p><h5><strong>Application to Real Samples</strong></h5><p>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<sup>–1</sup>. These values are below the MRL established by European Union regulation, which is 100 μg kg<sup>–1</sup>. <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.</p><p><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"></p><p>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<sup>–1</sup>. 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.</p><h4><strong>Conclusions</strong></h4><p>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.</p><p>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.</p><p>The pyrethroid permethrin was quantified in four cocoa samples. However, the concentrations did not exceed the MRL established by European Union legislation.</p><p>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.</p>

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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<p><strong>Measuring scattering samples with UV-VIS-NIR can be challenging for basic instruments. These samples will have diffuse reflectance or transmission and less light hitting your detector.</strong></p><p>In this presentation, we will discuss diffuse reflectance accessories (DRAs) for collecting all light in a measurement as well as Agilent's universal measurement accessory (UMA) for measuring the angular distribution of the reflected light.</p><blockquote><p><strong>Presenter:</strong> Scott Melis, PhD (Application Scientist, Agilent Technologies, Inc.)</p><p>Scott Melis has a PHD in Physics from Georgetown University in Washington, DC and started with Agilent in 2021 as a Molecular Spectroscopy Application Scientist. In his graduate work, Scott studied nanoparticle formation and growth for a variety of applications. Projects that he worked with include developing processes to deposit and characterize semiconducting molecular nano-cocrystals for use in optoelectronic devices as well as controlling polymer nanoparticle size through rapid mixing conditions.</p></blockquote>

Agilent Technologies: Measuring Diffuse Powders and Films With UV-VIS-NIR

Measuring Diffuse Powders and Films With UV-VIS-NIR

We will discuss diffuse reflectance accessories (DRAs) as well as Agilent's universal measurement accessory (UMA).

<div><div><div><div><div><div><article><div><div><div><div><div><div><article><div><div><div><div><div><div><article><div><div><div><div><div><div><p>Explore process analyzer options in this webinar, highlighting configurations, applications, and benefits for real-time monitoring in chemical and petrochemical industries.</p></div></div></div></div></div></div></article></div></div></div></div></div></div></article></div></div></div></div></div></div></article></div></div></div></div></div></div><blockquote><p><strong>Presenter:</strong> John Wasson</p><p>John Wasson has over 40 years of experience in Gas Chromatography and Chemical Instrumentation. He is President of Wasson-ECE Instrumentation, Inc.</p></blockquote>

Wasson-ECE Instrumentation: Free Webinar Series

Process Analyzer Options

Explore process analyzer options in this webinar, highlighting configurations, applications, and benefits for real-time monitoring in chemical industry.

<p><strong>The GC liner is one of the most important consumables for your GC inlet. GC inlets convert an injected liquid phase sample into gas for transfer onto the GC column. Selecting the wrong liner can lead to incomplete transfer, poor separation, and peak tailing—often incorrectly attributed to the GC system. As a result, you could waste valuable hours on troubleshooting. Join us as we discuss the different liners in our portfolio and help guide you in the selection process.</strong></p><blockquote><p><strong>Presenter: </strong>Alex Ucci (Application Engineer, Agilent Technologies, Inc.)</p><p>In his current position at Agilent, Alex provides application assistance and technical support for sample preparation products as well as GC and LC consumables. Before he joined Agilent in 2014, Alex was a graduate student at the Pennsylvania State University researching the morphology and surface properties of aerosol particles using a wide variety of analytical techniques. He has an MS degree in chemistry.</p></blockquote>

Agilent Technologies: Becoming a Better Chromatographer - Educational Webinar Series

The Right Liner for the Right Method: GC Inlet Essentials

Join us as we discuss the different liners in our portfolio and help guide you in the selection process.

Right Liner for Right Method: GC Inlet Essentials

<div><div><div><div><div><div><article><div><div><div><div><div><div><article><div><div><div><div><div><div><article><div><div><div><div><div><div><p>Mass spectrometry detector capabilities for compound identification and trace analysis in GC applications.</p></div></div></div></div></div></div></article></div></div></div></div></div></div></article></div></div></div></div></div></div></article></div></div></div></div></div></div><blockquote><p><strong>Presenter:</strong> John Wasson</p><p>John Wasson has over 40 years of experience in Gas Chromatography and Chemical Instrumentation. He is President of Wasson-ECE Instrumentation, Inc.</p></blockquote>

Specialty GC Detectors: The Strengths of Mass Spectrometry

Mass spectrometry detector capabilities for compound identification and trace analysis in GC applications.

<div><div><div><div><div><div><article><div><div><div><div><div><div><article><div><div><div><div><div><div><article><div><div><div><div><div><div><p>Converting carbon oxides to methane for FID detection, enabling ppm-level CO and CO2 quantification.</p></div></div></div></div></div></div></article></div></div></div></div></div></div></article></div></div></div></div></div></div></article></div></div></div></div></div></div><blockquote><p><strong>Presenter:</strong> John Wasson</p><p>John Wasson has over 40 years of experience in Gas Chromatography and Chemical Instrumentation. He is President of Wasson-ECE Instrumentation, Inc.</p></blockquote>

Methanizers for Trace CO and CO2

Converting carbon oxides to methane for FID detection, enabling ppm-level CO and CO2 quantification.

<p><strong>Learn incredible tricks and tips for maximizing your experience with </strong><a target="_blank" rel="noopener noreferrer" href="https://gcms.cz/products/305"><strong>Clarity Chromatography Software</strong></a><strong>. Dive into advanced functionalities and discover how to elevate your workflows.</strong></p><p><strong>We will closely look at Sequences and Calibrations.</strong></p><blockquote><p><a target="_blank" rel="noopener noreferrer" href="https://www.dataapex.com/training_reservation/149189"><strong>Register Here</strong></a></p></blockquote>

DataApex Clarity software Tips & Tricks Webinar

Learn incredible tricks and tips for maximizing your experience with Clarity Chromatography Software

<p><strong>For many GC–MS laboratories, sample preparation remains the biggest bottleneck. While traditional techniques like liquid–liquid extraction (LLE) and solid-phase microextraction (SPME) are well-established, they often force analysts to compromise on sensitivity, robustness, or automation capability, especially when dealing with complex matrices in food, environmental, and clinical research.</strong></p><p>In this webinar, Rachael Szafnauer from Markes International will take a deep dive into the fundamentals and practical applications of modern sorptive extraction. She will explore how high-capacity sorptive extraction bridges the gap between exhaustive extraction and equilibrium sampling, offering a robust, complementary technique for trace-level GC–MS analysis.</p><p>You will learn how to select the right phase and extraction mechanism for your target compounds, how to optimize key parameters like temperature and agitation, and how coupling sorptive extraction with cryogen-free trap focusing can significantly boost sensitivity.</p><h4><strong>Key learning objectives:</strong></h4><ul><li>Understand the fundamental differences between SPME, TF-SPME, and high-capacity sorptive extraction (HiSorb) regarding surface area and sensitivity.</li><li>Learn the considerations you must take when selecting the optimal sorptive phase and extraction mode (immersive vs. headspace) for your matrix.</li><li>Discover how analyte enrichment using a backflush, cryogen-free focusing trap can overcome the limitations of standard injection techniques.</li><li>See how these techniques are applied to complex samples, from aroma profiling in foods to contaminant monitoring.</li></ul><h4><strong>Who should attend?</strong></h4><ul><li>GC–MS analysts and researchers looking to improve sensitivity and workflow efficiency.</li><li>R&amp;D aroma and flavor scientists wanting to enhance their ability to extract and analyze complex samples.</li><li>Current users of SPME or stir-bar techniques looking for robust, high-capacity alternatives.</li><li>Laboratory managers and directors interested in how advanced automation can provide a competitive edge.</li></ul><h4><strong>Certificate of attendance</strong></h4><ul><li>If you attend the live webinar, you will automatically receive a certificate of attendance, including a learning outcomes summary, for continuing education purposes.</li><li>If you view the on-demand webinar, you can request a certificate of attendance by emailing editor@selectscience.net.</li></ul><blockquote><p><strong>Presenter:</strong> Rachael Szafnauer (Product Marketing Manager, Markes International Ltd)</p><p>Rachael Szafnauer received an M.Sci in forensic science from the University of South Wales, UK, where her final-year project focused on fingerprinting emerging psychoactive substances using advanced techniques such as GCxGC–TOF MS, in collaboration with Markes International. She later took up the role of thermal desorption product specialist at Markes, providing technical and application support to the commercial team, before taking on her current role as Product Marketing Manager for the Centri product line and specializing in the development of applications using extraction and enrichment techniques for GC–MS.</p><p><strong>Moderator: </strong>Olivia Long (Editorial Team, SelectScience)</p></blockquote>

Markes International: Mastering sorptive extraction for GC–MS

Mastering sorptive extraction for GC–MS

Rachael Szafnauer from Markes International will take a deep dive into the fundamentals and practical applications of modern sorptive extraction

<div><div container-id="cq-colctrl-lt0" comp-id="A1"><div><p><strong>Silvia Aguiló Losa has been instrumental in bringing truly comprehensive mineral oil hydrocarbon (MOSH/MOAH) analysis into a routine testing environment at SGS Institut Fresenius (Berlin, Germany), using LECO’s two-dimensional gas chromatography time-of-flight mass spectrometer (GCxGC-TOFMS) and dual flame ionization detector (FID) workflows.</strong></p><p>In this webinar, she will show how coupling GCxGC-TOFMS-FID technology with liquid chromatography techniques uncovers hidden interferences, resolves complex hydrocarbon “humps,” and provides the mass-spectral confirmation needed to avoid false positives and deliver robust, defensible results.</p><p>Silvia will share practical insights from her daily work at SGS, where LECO’s GCxGC technologies have enabled routine differentiation of MOSH/MOAH fractions, identification of critical markers and confident assessment of samples under increasing regulatory pressure.</p><p>Additionally, Silvia will discuss the updated MOH Guidance for GCxGC Analysis provided by the European Union Reference Laboratory for Processing Contaminants.</p><p>This session is ideal for food-safety, packaging, and compliance laboratories looking to elevate their MOSH/MOAH testing with workflows that are both comprehensive and operationally realistic for routine use.</p><blockquote><p><strong>Presenter: </strong>Silvia Aguiló Losa (Team Leader/Product Manager Mineral Oils Analysis, SGS Institut Fresnius GmbH)</p></blockquote></div></div></div>

LECO: What You Don’t See: Beyond Routine Analysis with LC–GCxGC-TOFMS–FID

What You Don’t See: Beyond Routine Analysis with LC–GCxGC-TOFMS–FID

Webinar on GCxGC-TOFMS-FID for MOSH/MOAH analysis, featuring SGS case studies, LC coupling, EU MOH guidance, and reliable workflows for routine labs.

Beyond Routine Analysis with LC–GCxGC-TOFMS–FID

<div><div container-id="cq-colctrl-lt0" comp-id="A1"><div><p><strong>Take your Chromeleon Instrument Methods to the next level with this focused and practical session. This webinar is specifically designed for Thermo Scientific Chromeleon CDS users, who want to enhance their current skills and gain a better understanding of how to control instrument actions and apply dynamic sequence logic.</strong></p><h4><strong>Topics covered include:</strong></h4><ul><li><strong>Script editor overview:</strong> Understand the basics of writing and editing custom scripts</li><li><strong>Conditional statements:</strong> Learn how to use logic to make conditional decisions during runs and sequences</li><li><strong>Information logging:</strong> Record key instrument and method events in real time for extended audit trail coverage</li><li><strong>Custom sequence variables: </strong>Control sequence and instrument behavior and with user-defined fields to enrich meta data capture</li><li><strong>User-defined programs:</strong> Customize injection actions to support complex workflows</li><li><strong>Automated startup and shutdown: </strong>Create routines to prepare instruments for operation or safely power them down</li></ul><h4><strong>Why Attend:</strong></h4><p>Join this webinar to gain practical skills and expert tips for using Chromeleon CDS more effectively. Whether you’re new or experienced, you’ll learn how to streamline workflows and enhance your analytical instrument methods.</p><p><strong>Cannot attend the live broadcast?&nbsp;</strong></p><p><i>Please register anyway, and we will automatically send you the link to the recording.</i></p><blockquote><p><strong>Presenter: </strong>Peter Zipfell (Product Marketing Manager, Thermo Fisher Scientific)</p></blockquote></div></div></div>

Thermo Fisher Scientific: Get more from your Chromeleon Instrument Methods

Get more from your Chromeleon Instrument Methods

Join this webinar to gain practical skills and expert tips for using Chromeleon CDS more effectively.

<div><div container-id="cq-colctrl-lt0" comp-id="A1"><div><p><strong>There are as many solutions available for MOSH/MOAH analysis as there are matrices. Every matrix requires a special clean up. Maybe you are done with one step, maybe it requires several steps to accomplish a proper result.</strong></p><p>The EN16995 changes very often. You have questions about the changes you would like to know how to use GC X GC MS technology to qualify your results?</p><p>Ask our experts live!</p><h4><strong>Learning points</strong></h4><ul><li>An opportunity for you to ask our MOSH/MOAH experts any of your burning questions</li><li>The new Maurus Biedermann approach with GC X GC/MS</li></ul><h4><strong>Who should attend?</strong></h4><ul><li>Users looking to enhance their current MOSH/MOAH analysis</li><li>Users who are looking to overcome their current MOSH/MOAH analysis challenges within their laboratory</li><li>Users looking to gain more experience in MOSH/MOAH analysis</li><li>If you cannot attend this webinar please register to receive a link to the On Demand version the following day.</li></ul><blockquote><p><strong>Presenter:&nbsp;</strong>Jorn Hofsteenge (Application Scientist, SampleQ, Breda, The Netherlands)</p><p>Jorn is since many years a part of the applications team at SampleQ and specialized in the analysis of MOSH/MOAH. Working globally directly with customers to set up the newest technology for MOSH/MOAH analysis.</p><p><strong>Presenter: </strong>Petra Gerhards (Regional Marketing Manager GC &amp; GC-MS, EMEA, Thermo Fisher Scientific)</p><p>Her background is over 30 years of experience in the field of GC-MS, SPE and LC-MS. Joined the EMEA Regional Marketing Team in 2016. She has been involved in a lot of workflow solutions combining vials and closures with SPE solutions, GC-MS and LC-MS. She works with KOL`s on data for regional specific marketing campaigns, organizes inhouse seminars and works on customer specific solutions. Her main expertise is in the field of doping and drugs of abuse analysis.</p></blockquote></div></div></div>

Thermo Fisher Scientific: Talk to an expert about our barrier-free analysis of MOSH/MOAH

Talk to an expert about our barrier-free analysis of MOSH/MOAH

Live Q&A webinar on MOSH/MOAH analysis covering EN 16995 changes, matrix-specific cleanup, and the Maurus Biedermann GC×GC/MS approach with expert insights.

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