EU Regulation 396/2005: Pesticide Residue Testing and the Critical Role of QuEChERS Evaporation in Food Safety

<div><div><p><strong>Researchers led by </strong><a target="_blank" rel="noopener noreferrer" href="https://kudova.group.uochb.cz/en"><strong>Eva Kudová</strong></a><strong> from IOCB Prague and Jitka Viktorová from UCT Prague have identified new androstane-based steroid derivatives that can significantly improve the effectiveness of existing antibiotics against multidrug-resistant </strong><i><strong>Staphylococcus aureus</strong></i><strong>.</strong></p></div></div><div><p>The team screened dozens of natural steroidal hormones and synthetic derivatives to see whether they could block bacterial efflux pumps – mechanisms that bacteria use to eject antibiotics and survive treatment. Two compounds emerged as particularly promising: they inhibited efflux pumps and lowered the effective doses of antibiotics such as ciprofloxacin and erythromycin.</p><p>Further analysis showed that one of the compounds also suppressed genes linked to bacterial virulence. Another key finding is that the most active molecules are non-toxic to human immune cells and showed no detectable endocrine activity, suggesting a favorable safety profile.</p><p>These findings support the idea that rationally designed steroid-based molecules could act as antibiotic adjuvants, helping existing drugs overcome bacterial resistance.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/IOCB_Prague_Steroidal_hormones_and_neurosteroids_novel_therapeutic_strategies_in_bacterial_infections_8e5d2a7b48.jpg" alt="IOCB Prague: Steroidal hormones and neurosteroids – novel therapeutic strategies in bacterial infections" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_IOCB_Prague_Steroidal_hormones_and_neurosteroids_novel_therapeutic_strategies_in_bacterial_infections_8e5d2a7b48.jpg 222w," sizes="100vw" width="1258" height="886"></p><blockquote><h4><strong>Original Article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://www.sciencedirect.com/science/article/pii/S0223523426001613?via%3Dihub"><strong>Steroidal hormones and neurosteroids - novel therapeutic strategies in bacterial infections: Design, synthesis, and biological evaluation</strong></a></h4><p>Daniela Brdová, Bára Křížkovská, Jan Špaček, Zdeněk Míchal, Eva Jablonská, Ondřej Strnad, Hana Chodounská, Eszter Szánti-Pintér, Marina Morozovová, Václav Hanžl, Jan Tkadlec, Martijn Riool, Jan Lipov, Jitka Viktorová, Eva Kudová&nbsp;</p><p><i><strong>Eur. J. Med. Chem., 2026, 308, 118716</strong></i></p><p><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1016/j.ejmech.2026.118716">https://doi.org/10.1016/j.ejmech.2026.118716</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>The global rise of antibiotic resistance necessitates novel therapeutic strategies for infectious diseases. Inhibition of bacterial efflux pumps, which contribute to multidrug resistance, represents a promising approach to restore or even increase the efficacy of existing antibiotics. Using fluorescence-based ethidium bromide accumulation, broth microdilution, and checkerboard assays, we evaluated 26 endogenous steroidal hormones and neurosteroids, along with 30 synthetic derivatives, for their ability to enhance antibiotic susceptibility in multidrug-resistant <i>Staphylococcus aureus</i>. Structure-activity relationship analysis identified compounds <strong>13</strong> and <strong>16</strong> as lead candidates, exhibiting strong efflux pump inhibition and marked reductions in the minimum inhibitory concentrations of ciprofloxacin and erythromycin. Both compounds showed additive effects in checkerboard assays. Modifications at C-3 (polar substitution) and C-17 (3α,5β-stereochemistry and nonpolar substitution) were essential for potent efflux inhibition and sensitization, although these modifications were not additive when combined. Transcriptome analysis further revealed that compound <strong>13</strong> significantly downregulated <i>S. aureus</i> virulence-associated genes when administered alone or in combination with antibiotics. Cytotoxicity assessment in human peripheral blood mononuclear cells and receptor transactivation assays for estrogen, androgen, and progesterone receptors indicated that the most active derivatives were non-toxic and lacked detectable endocrine activity, suggesting a favorable safety profile. Overall, these findings support the concept that rationally designed andostane-based steroidal scaffolds can function as competitive bacterial efflux pump inhibitors and serve as potential antibiotic adjuvants to mitigate efflux-mediated resistance.</p><h4><strong>Instrumentation</strong></h4><h5><strong>Structural characterization</strong></h5><ul><li><strong>AVANCE III 400 MHz NMR spectrometer</strong> (Bruker)</li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/library?mainauthorItems=3&amp;search=LTQ+Orbitrap+XL"><strong>LTQ Orbitrap XL HRMS</strong></a> (Thermo Fisher Scientific, ESI)</li></ul></div>

Steroidal hormones and neurosteroids – novel therapeutic strategies in bacterial infections

<p><strong>Metformin is currently the first-line oral drug of choice for the treatment of type 2 diabetes. It reduces glucose production in the liver, improves tissue sensitivity to insulin, and does not cause weight gain or hypoglycemia, which sets it apart from some other antidiabetic drugs. Moreover, its long-term beneficial effects on the risk of cardiovascular complications and mortality in people with type 2 diabetes have been well established. Researchers from the Institute of Physiology CAS (IPHYS) have identified a new group of blood metabolites that could help physicians objectively monitor whether patients with type 2 diabetes are taking their metformin as prescribed.</strong></p><h4><strong>New biomarkers for metformin use</strong></h4><p>A team led by Tomáš Čajka from the Laboratory of Translational Metabolism at IPHYS analyzed plasma samples from <strong>637 patients with type 2 diabetes treated with metformin</strong> and <strong>143 non-diabetic controls</strong> using advanced metabolomics and lipidomics. Among 614 detected metabolites, they identified five from the group of <strong>N-lactoyl-amino acids </strong>(e.g. N‑lactoyl-phenylalanine), which had previously been seen as unknown signals due to missing reference spectra in databases. The levels of these metabolites in the blood closely reflected the plasma concentrations of metformin. In patients with the highest metformin exposure, the concentrations of these metabolites were up to 7.2 times higher than in controls.</p><h4><strong>A sensitive “fingerprint” of the drug’s effect</strong></h4><p>N-Lactoyl-amino acids are formed in cells by combining lactate and amino acids, thus reflecting the metformin-induced changes in cellular energy metabolism. “<i>Importantly, even though they occur in plasma only at nanomolar concentrations, they reliably distinguish patients who take metformin regularly from those who take it irregularly or not at all</i>,” emphasizes T. Čajka.</p><h4><strong>Metabolomics in practice and international collaboration</strong></h4><p>The study also provides a detailed description of broader metabolic changes in type 2 diabetes, including increases in lactate, organic acids, and branched-chain amino acids, as well as extensive remodelling of the lipid profile. In addition to T. Čajka’s team, collaborators from the Institute for <strong>Clinical and Experimental Medicine in Prague</strong> and the <strong>West Coast Metabolomics Center</strong> (University of California, Davis) also participated in the study.</p><p>The results demonstrate that advanced metabolomics approaches developed at IPHYS within the <strong>CarDia project</strong> can find highly practical applications both in clinical studies and in personalized monitoring of treatment in patients with diabetes.</p><blockquote><h4><strong>The original article</strong></h4><h4><a target="_blank" rel="noopener noreferrer" href="https://ascpt.onlinelibrary.wiley.com/doi/10.1002/cpt.70205"><strong>Untargeted Metabolomics Identifies N-Lactoyl-Amino Acids as Dose-Responsive Plasma Biomarkers of Metformin Adherence in Type 2 Diabetes</strong></a></h4><p>Tomas Cajka, Jiri Hricko, Lucie Rudl Kulhava, Michaela Paucova, Michaela Novakova, Veronika Hola, Stanislava Rakusanova, Oliver Fiehn, Vojtech Skop, Ivana Lankova, Iva Miskova, Terezie Pelikanova, Martin Haluzik</p><p>Clin Pharmacol Ther, 119: 1057-1069</p><p><a target="_blank" rel="noopener noreferrer" href="https://doi.org/10.1002/cpt.70205">https://doi.org/10.1002/cpt.70205</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>Metformin is the most widely prescribed antidiabetic drug, yet adherence remains difficult to objectively assess. Using untargeted metabolomics and lipidomics, we analyzed plasma from 637 patients with type 2 diabetes (T2D) with confirmed metformin use and 143 nondiabetic controls, annotating 614 metabolites. Patients were stratified by plasma metformin into sub-therapeutic, therapeutic, and supra-therapeutic groups, and associations were evaluated by multiple linear regression and composite metabolite ranking. Five previously unannotated features were structurally identified as N-lactoyl-amino acids, whose levels correlated strongly with plasma metformin (ρ = 0.42–0.55, P &lt; 0.0001) and increased up to 7.2-fold in the supra-therapeutic group (&gt; 2000 ng/mL). While N-lactoyl-amino acids were consistently detected in the nanomolar range, they still displayed robust and dose-dependent associations with metformin. Broader metabolic changes in T2D included elevated lactate, organic acids, and branched-chain amino acids, together with reduced urea cycle metabolites. Lipidomics showed increases in saturated triacylglycerols and diacylglycerols and decreases in cholesteryl esters, sphingomyelins, and phospholipids. These findings establish N-lactoyl-amino acids as robust, dose-responsive plasma biomarkers of metformin exposure. Despite being up to four orders of magnitude less abundant than their amino acid precursors, they sensitively reflect mitochondrial lactate overflow and pharmacodynamic adaptation, offering objective assessment of adherence.</p>

New blood biomarkers reveal how faithfully diabetes patients take metformin

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The Czech Academy of Sciences (CAS) was established by Act No. 283/1992 Coll. as the Czech successor of the former Czechoslovak Academy of Sciences. It is set up as a complex of 54 public research institutions.

Czech Academy of Sciences

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

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

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Waters Oasis SPE products

Waters Oasis SPE products come in a broad range of sorbents and an array of formats. With Oasis products, you can meet a wide variety of sample preparation needs.

<h4><strong>Faster, cleaner, and simpler SPE starts here</strong></h4><p>Analytical chemists worldwide use SPE to remove interfering matrix compounds and enrich the analyte of interest to ensure the generation of high-quality data.</p><p>Waters Oasis SPE products come in a broad range of sorbents and an array of formats. With Oasis products, you can meet a wide variety of sample preparation needs, from simple and fast sample matrix clean-up to more complex sample preparation challenges.</p><p>Oasis SPE products deliver unmatched purity, consistency, and quality for sample analysis. Along with seven different SPE chemistries, Oasis SPE products use universal to customized protocols to handle your unique sample.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Oasis_SPE_kolonky_2_967d461f2e/Waters-Oasis-SPE-kolonky-2.jpg" alt="Waters: Oasis SPE" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Oasis_SPE_kolonky_2_967d461f2e/thumbnail_Waters-Oasis-SPE-kolonky-2.jpg 245w," sizes="100vw" width="950" height="416"></p><h4><strong>Overview</strong></h4><ul><li>Fully water-wettable sorbents increase reproducibility and enable elimination of condition and equilibration steps</li><li>Co-polymer pH stable from 0–14 with no secondary silanol activity</li><li>Optimal sensitivity for small molecule and therapeutic peptide analysis</li><li>Reduced matrix effects for LC-MS/MS analyses</li><li>Unsurpassed selectivity</li><li>Consistent retention and capacity, yielding the highest SPE recovery</li><li>Reduces variability in analytical results and increases robustness of analysis</li><li><strong>Recommended Use: </strong>For the fastest, cleanest, and simplest approach to SPE-LC-MS/MS method development.</li></ul><h4><strong>Solid-Phase Extraction Chemistries</strong></h4><h5><strong>Oasis PRiME HLB</strong></h5><ul><li>Multi-purpose hydrophilic-lipophilic balanced reversed phase sorbent for acids, bases, and neutrals</li><li>Cleaner samples in fewer steps with simple three-and two-step protocols, no SPE expertise required</li><li>Removes 95% of common matrix interferences, such as proteins, salts, phospholipids, and pigments</li><li>No sorbent conditioning or equilibration steps required</li><li>Faster, more predictable analysis time</li><li>Ideal for reversed-phase SPE clean-up of samples in routine analysis.</li></ul><h5><strong>Oasis PRiME MCX</strong></h5><ul><li>Mixed-mode Cation eXchange sorbent to selectively retain, concentrate and elute basic compounds</li><li>Reversed-phase and ion-exchange functionality for orthogonal sample preparation</li><li>Cleaner samples in fewer steps with simple and fast 3 and 4-step protocols</li><li>Removes 99% of phospholipids from complex sample matrices</li><li>No sorbent conditioning or equilibration steps required</li><li>Faster, more predictable analysis time</li><li>Highly reproducible target analyte recoveries</li><li>Ideal for basic compound specificity while removing matrix interferences in a simple clean-up.</li></ul><h5><strong>Oasis HLB</strong></h5><ul><li>Multi-purpose hydrophilic-lipophilic balanced reversed phase sorbent</li><li>Provides high capacity for acids, bases, and neutrals</li><li>Ideal for ultra-high capacity of very polar compounds.</li></ul><h5><strong>Oasis MCX</strong></h5><ul><li>Mixed-mode Cation eXchange sorbent for bases</li><li>Increased analyte specificity and sensitivity</li><li>Reversed-phase and ion-exchange functionality for orthogonal sample preparation</li><li>Ideal for selective retention of basic analytes.</li></ul><h5><strong>Oasis MAX</strong></h5><ul><li>Mixed-mode Anion eXchange for acids</li><li>Increased analyte specificity and sensitivity</li><li>Reversed-phase and ion-exchange functionality for orthogonal sample preparation</li><li>Ideal for selective retention of acidic analytes.</li></ul><h5><strong>Oasis WAX</strong></h5><ul><li>Weak Anion eXchange mixed-mode sorbent for strong acidic compounds</li><li>Increased analyte specificity and sensitivity</li><li>Reversed-phase and ion-exchange functionality for orthogonal sample preparation</li><li>Ideal for improved retention of strong acidic compounds.</li></ul><h5><strong>Oasis WCX</strong></h5><ul><li>Weak Cation eXchange mixed-mode sorbent for strong basic compounds</li><li>Increased analyte specificity and sensitivity</li><li>Reversed-phase and ion-exchange functionality for orthogonal sample preparation</li><li>Ideal for improved retention of all basic analytes, especially strong bases.</li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Sorbenty_Oasis_SPE_na_bazi_kopolymeru_Oasis_HLB_c8ffee39b3/Waters-Sorbenty-Oasis-SPE-na-bazi-kopolymeru-Oasis-HLB.png" alt="Waters: Oasis Sorbents" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Sorbenty_Oasis_SPE_na_bazi_kopolymeru_Oasis_HLB_c8ffee39b3/thumbnail_Waters-Sorbenty-Oasis-SPE-na-bazi-kopolymeru-Oasis-HLB.png 211w," sizes="100vw" width="1511" height="1119"></p><h4><strong>Oasis Formats</strong></h4><h5><strong>Oasis μElution Plate</strong></h5><ul><li>Patented μElution plate design</li><li>No evaporation and reconstitution necessary due to elution volumes as low as 25 µL</li><li>Ideal for SPE clean-up and analyte enrichment of small sample volumes</li><li>Compatible with most liquid-handling robotic systems for automated, reliable high-throughput SPE (HT-SPE)</li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Corporation_Oasis_m_Elution_Plate_aa7e36a4c1.jpg" alt="Waters: Oasis µElution Plate" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Corporation_Oasis_m_Elution_Plate_aa7e36a4c1.jpg 245w," sizes="100vw" width="502" height="260"></p><h5><strong>Oasis 96-Well Sample Extraction Plates</strong></h5><ul><li>Innovative, award-winning two-stage well design</li><li>High throughput and high recovery</li><li>Compatible with most liquid-handling robotic systems for automated, reliable high-throughput SPE (HT-SPE)</li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Corporation_Oasis_96_Well_Sample_Extraction_Plates_9528d532b9.jpg" alt="Waters: Oasis 96-Well Sample Extraction Plates" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Corporation_Oasis_96_Well_Sample_Extraction_Plates_9528d532b9.jpg 245w," sizes="100vw" width="525" height="329"></p><h5><strong>Oasis Syringe-Barrel Cartridges</strong></h5><ul><li>Ultra-clean syringe barrel and frits</li><li>Available in cartridges ranging from 1 cc to 60 cc</li><li>Flangeless syringe-barrel cartridges available in 1 cc, 3 cc, and 6 cc sizes</li><li>Plus-style cartridges with Luer inlet hub and outlet tip, compatible with hand-held syringes</li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Corporation_Oasis_Syringe_Barrel_Cartridges_961aa06b8a.jpg" alt="Waters Corporation: Oasis Syringe-Barrel Cartridges" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Corporation_Oasis_Syringe_Barrel_Cartridges_961aa06b8a.jpg 245w," sizes="100vw" width="503" height="311"></p><h5><strong>Oasis Glass Cartridges</strong></h5><ul><li>Ultra-clean glass syringe with Teflon® frit</li><li>For trace level detection and analysis at part-per-trillion (PPT) levels</li><li>Available in 5 cc (200 mg) configuration</li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Corporation_Oasis_Glass_Cartridges_5e96319c7f.jpg" alt="Waters: Oasis Glass Cartridges" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Corporation_Oasis_Glass_Cartridges_5e96319c7f.jpg 188w," sizes="100vw" width="409" height="339"></p><h5><strong>Oasis On-Line Columns and Cartridges</strong></h5><ul><li>For rugged, reproducible, and ultra-fast on-line analysis</li><li>Wide choice of configurations, particle sizes, and sorbent chemistries</li><li>Available with all six patented Oasis sorbents—PRiME HLB, HLB, MCX, MAX, WCX, and WAX</li><li>High recovery and reproducible results for a wide range of compounds</li><li>Cartridge format for use with Spark Holland Prospekt-2™/Symbiosis™ systems also available</li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Corporation_Oasis_On_Line_Columns_and_Cartridges_ba02114c92.jpg" alt="Waters: Oasis On-Line Columns and Cartridges" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Corporation_Oasis_On_Line_Columns_and_Cartridges_ba02114c92.jpg 168w," sizes="100vw" width="415" height="386"></p><h4><strong>Sample preparation, improved</strong></h4><p>Improving various aspects of chromatography and mass spectrometry analyses often starts with sample preparation. &nbsp;Solid-phase extraction (SPE) or "liquid-solid phase extraction" is a sample preparation technology that uses particles of chromatographic packing material, usually in a cartridge or 96-well plate format, to chemically separate different analytes and aid in removing matrix components in a sample. &nbsp;</p><p>SPE is a proven sample preparation tool for simple sample matrix removal, including common interferences like proteins, salts, fats and phospholipids. This matrix removal provides many benefits, including matrix effect reduction and an increase in sample concentration and analyte specificity. Matrix removal also significantly simplifies chromatographic complexity by reducing the number of interfering peaks in the LC and reducing signal suppression by providing clean samples for the MS.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Corporation_Oasis_SPE_LC_MS_MS_chromatogram_of_1_pgm_L_of_alprazolam_from_rat_plasma_8b7275b25b.jpg" alt="Waters: Oasis SPE - LC-MS-MS chromatogram of 1 pgmL of alprazolam from rat plasma" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Corporation_Oasis_SPE_LC_MS_MS_chromatogram_of_1_pgm_L_of_alprazolam_from_rat_plasma_8b7275b25b.jpg 169w," sizes="100vw" width="1024" height="946"></p><h4><strong>Get the cleanest extracts with the Oasis 2x4 method</strong></h4><p>Having a variety of tools for method development allows separation scientists to optimize protocols for maximum sensitivity and selectivity. The Oasis 2x4 method for SPE sorbent and protocol selection for acids, bases, and neutrals produces the cleanest extracts – all by eliminating matrix interferences and sample variability. Get the flexibility to extract acids, bases, and neutrals with high SPE recoveries while removing matrix components that may interfere with analysis with our two protocols and four sorbents. By following the simple steps outlined in the Oasis 2x4 method, you can achieve high recoveries and the cleanest extracts.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Oasis_2x4_protokol_pro_vyvoj_metody_c417be9006/Waters-Oasis-2x4-protokol-pro-vyvoj-metody.jpg" alt="Waters: Oasis SPE - Oasis 2 x 4 method development protocol." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Oasis_2x4_protokol_pro_vyvoj_metody_c417be9006/thumbnail_Waters-Oasis-2x4-protokol-pro-vyvoj-metody.jpg 242w," sizes="100vw" width="1519" height="979"></p><h4><strong>Isolate your compounds with the Oasis HLB method</strong></h4><p>Solid-phase extraction (SPE) method development starts with knowledge of the sample matrix—the nature and relative concentration of the analytes of interest and potentially interfering endogenous compounds. The right sorbent and solvents are selected for load, wash, and elute steps, resulting in the creation of rugged, reliable, and selective protocols. The Oasis HLB method is a generic protocol used to isolate a broad range of acidic, basic, and neutral compounds from a wide spectrum of matrices.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Corporation_Oasis_SPE_Generic_Method_Protocol_with_Oasis_HLB_SPE_83d684704d.jpg" alt="Waters: Oasis SPE - Generic Method Protocol with Oasis HLB SPE" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Corporation_Oasis_SPE_Generic_Method_Protocol_with_Oasis_HLB_SPE_83d684704d.jpg 139w," sizes="100vw" width="1024" height="1153"></p><h4><strong>Multiple contaminant analysis with the 2-step pass-through protocol</strong></h4><p>If you are doing multiple residue screening of veterinary drugs, pesticides and mycotoxins in various food matrices, you may be facing a high concentration of organic solvents. With our simple 2-step protocol (pass-through SPE), you can remove matrix interferences quickly if your samples contain a high concentration of organic solvent(s) and concentration and/or salt removal is not required. It can be used as the clean-up method following QuEChERS extraction, saving you significant time compared to the traditional dispersive SPE method - all while achieving superior clean-up.</p><p><strong>To do pass-through SPE, Waters offers 2 convenient and flexible formats:</strong></p><ul><li><strong>Traditional-style cartridges</strong> compatible with vacuum and positive pressure manifolds&nbsp;</li><li><strong>"Plus" style cartridges</strong> that can be used without manifolds when connected to a displacement syringe</li></ul><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Oasis_SPE_kolonky_3_b4da6242de/Waters-Oasis-SPE-kolonky-3.jpg" alt="Waters: Oasis Plus Light and Plus Short Cartridges for 2-step pass through protocol." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Oasis_SPE_kolonky_3_b4da6242de/thumbnail_Waters-Oasis-SPE-kolonky-3.jpg 152w," sizes="100vw" width="1308" height="1342"></p>

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New blood biomarkers reveal how faithfully diabetes patients take metformin

Steroidal hormones and neurosteroids – novel therapeutic strategies in bacterial infections

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