Meeting EU Drinking Water Standards: The Critical Role of Sample Prep in Trace Contaminant Analysis

<h3><strong>Charged for Action: The Hidden Secrets of AEX Oligonucleotide Analysis</strong></h3><p><strong>Oligonucleotides—short, well-defined fragments of DNA or RNA—have become indispensable tools in modern life sciences. They underpin cutting-edge applications in molecular diagnostics, gene therapy, and pharmaceutical development. Before oligonucleotides can be confidently used in research or clinical settings, however, their quality must be rigorously assessed. Purity, sequence integrity, length distribution, and chemical modifications all play a decisive role in their performance.</strong></p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Oligos_Made_Easy_Part_2_AEX_2_45eee54fa0.jpg" alt="KNAUER: Oligos Made Easy - Part 2: AEX" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Oligos_Made_Easy_Part_2_AEX_2_45eee54fa0.jpg 245w," sizes="100vw" width="1534" height="711"></p><p>Among the analytical techniques available today, <strong>anion exchange chromatography (AEX)</strong> stands out as a robust and highly informative method for characterizing oligonucleotides. By exploiting their intrinsic negative charge, AEX provides detailed insight into product composition and impurity profiles that are difficult to obtain by other approaches.</p><blockquote><p><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/article/6808"><strong>Part 1 of the Oligos series: A Practical Guide to Oligonucleotide Production – From Concept to Final Product</strong></a></p></blockquote><h4><strong>How Scientists Read Oligonucleotides Using Charge</strong></h4><p>At the core of AEX lies a simple but powerful principle: oligonucleotides carry a negatively charged phosphate backbone. This charge increases in a predictable way with strand length and, to a lesser extent, sequence composition. Anion exchange chromatography uses this property to separate oligonucleotides based on differences in charge strength and interaction with a positively charged stationary phase.</p><p>As a result, AEX has become one of the most widely used analytical tools for evaluating oligonucleotide quality. It allows scientists to distinguish full-length products from truncated species, degradation products, or closely related variants—often with single-nucleotide resolution.</p><h4><strong>Why Ion Exchange Works: Binding, Retention, and Release</strong></h4><p>Ion exchange chromatography (IEX) relies on electrostatic interactions between analytes and a charged stationary phase. In the case of oligonucleotides, <strong>anion exchange</strong> is used, where negatively charged molecules interact with positively charged functional groups on the resin—most commonly quaternary amines.</p><p>The system consists of two main components:</p><ul><li><strong>Stationary phase:</strong> A positively charged resin that binds anionic analytes.</li><li><strong>Mobile phase:</strong> An aqueous buffer system, typically combined with a salt gradient, that controls both pH and elution strength.</li></ul><p>Retention in AEX is governed primarily by charge. Molecules with weaker overall charge interact less strongly with the stationary phase and elute earlier, while more highly charged oligonucleotides bind more tightly and require stronger elution conditions.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Oligos_Made_Easy_Part_2_AEX_Figure_1_IEX_overview_including_elution_order_dependency_on_analyte_charge_3419ad3075.jpg" alt="KNAUER: Oligos Made Easy - Part 2 AEX: Figure 1 IEX overview including elution order dependency on analyte charge." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Oligos_Made_Easy_Part_2_AEX_Figure_1_IEX_overview_including_elution_order_dependency_on_analyte_charge_3419ad3075.jpg 245w," sizes="100vw" width="1583" height="654"></p><h4><strong>The Five-Step Workflow of Ion Exchange Chromatography</strong></h4><p>AEX separations generally follow a well-established sequence of steps:</p><ol><li><strong>Column equilibration</strong><br>The column is conditioned with the starting buffer until the baseline and pH are stable. This ensures that all charged sites on the resin are ready for interaction.</li><li><strong>Sample loading</strong><br>Samples, prepared in the starting buffer, are introduced under conditions that promote binding of the target oligonucleotides while minimizing retention of unwanted impurities.</li><li><strong>Washing</strong><br>The column is washed with the starting buffer to remove uncharged or weakly interacting components. The baseline stabilizes as these species are flushed away.</li><li><strong>Elution</strong><br>Bound oligonucleotides are released using a salt or pH gradient. Increasing ionic strength introduces competing ions that displace the analytes from the resin. Weakly bound species elute first; strongly charged oligonucleotides elute later.</li><li><strong>Regeneration and re-equilibration</strong><br>A high-salt buffer removes any remaining bound material. The column is then returned to starting conditions in preparation for the next analysis.</li></ol><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Oligos_Made_Easy_Part_2_AEX_Figure_2_Five_steps_of_IEX_procedure_in_blue_outlined_using_an_example_chromatogram_in_red_38dd70b1b1.jpg" alt="KNAUER: Oligos Made Easy - Part 2 AEX: Figure 2  Five steps of IEX procedure (in blue), outlined using an example chromatogram (in red)." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Oligos_Made_Easy_Part_2_AEX_Figure_2_Five_steps_of_IEX_procedure_in_blue_outlined_using_an_example_chromatogram_in_red_38dd70b1b1.jpg 245w," sizes="100vw" width="1583" height="674"></p><h4><strong>Why AEX Is Especially Effective for Oligonucleotides</strong></h4><p>The repeating phosphate backbone of oligonucleotides gives rise to a strong and uniform anionic character across a wide pH range (typically pH 7–9). This makes oligonucleotides exceptionally well suited for anion exchange separations.</p><p>Key factors influencing AEX behavior include:</p><ul><li><strong>Charge density:</strong> Longer oligonucleotides carry more negative charges and therefore exhibit stronger retention.</li><li><strong>Resin chemistry:</strong> Strong and weak anion exchangers differ in functional groups and pH stability, influencing selectivity and robustness.</li><li><strong>Buffer composition:</strong> The choice of buffering ions and salt gradients directly affects elution strength and resolution.</li></ul><p>Salt gradients—commonly based on chloride ions—compete with the oligonucleotide backbone for binding sites on the resin. By carefully tuning gradient slope and composition, analysts can achieve highly reproducible and finely resolved separations.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Oligos_Made_Easy_Part_2_AEX_Figure_3_Ionic_interactions_and_p_H_influence_on_Anion_Exchange_Chromatography_AEX_612e231ba4.jpg" alt="KNAUER: Oligos Made Easy - Part 2 AEX: Figure 3 Ionic interactions and pH influence on Anion Exchange Chromatography (AEX)." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Oligos_Made_Easy_Part_2_AEX_Figure_3_Ionic_interactions_and_p_H_influence_on_Anion_Exchange_Chromatography_AEX_612e231ba4.jpg 245w," sizes="100vw" width="1547" height="593"></p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Oligos_Made_Easy_Part_2_AEX_Figure_4_AEX_buffer_selection_and_gradient_strategy_chromatogram_with_red_buffer_gradient_curve_53fd1bb11b.jpg" alt="KNAUER: Oligos Made Easy - Part 2 AEX: Figure 4 AEX buffer selection and gradient strategy (chromatogram with red buffer gradient curve)." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Oligos_Made_Easy_Part_2_AEX_Figure_4_AEX_buffer_selection_and_gradient_strategy_chromatogram_with_red_buffer_gradient_curve_53fd1bb11b.jpg 245w," sizes="100vw" width="1600" height="327"></p><h4><strong>AEX as the Gold Standard for Oligonucleotide Separation</strong></h4><p>Anion exchange chromatography has become the method of choice for both analytical and preparative oligonucleotide workflows. Its advantages include:</p><ul><li><strong>High resolving power:</strong> Closely related impurities, including n–1 or n–2 species, can often be separated and quantified.</li><li><strong>Predictable retention behavior:</strong> In many cases, retention time correlates linearly with oligonucleotide length, simplifying identification.</li><li><strong>Compatibility with modified oligonucleotides:</strong> Even chemically modified sequences retain their anionic nature, allowing AEX to resolve both products and related impurities.</li><li><strong>Excellent control via gradient elution:</strong> Salt gradients provide precise tuning of selectivity and resolution.</li></ul><p>Typically, shorter or degraded oligonucleotides elute at lower ionic strength, while full-length products with higher charge density appear later in the chromatogram.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/KNAUER_Oligos_Made_Easy_Part_2_AEX_Figure_5_AEX_Advantages_and_Challenges_7835521e34.jpg" alt="KNAUER: Oligos Made Easy - Part 2 AEX: Figure 5 AEX Advantages and Challenges." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_KNAUER_Oligos_Made_Easy_Part_2_AEX_Figure_5_AEX_Advantages_and_Challenges_7835521e34.jpg 245w," sizes="100vw" width="1535" height="707"></p><h4><strong>Final Perspective: Mastering AEX with Confidence</strong></h4><p>Anion exchange chromatography may appear complex at first, but with thoughtful optimization of pH, buffer composition, and gradient conditions, it becomes a highly precise and reliable tool for oligonucleotide analysis. When properly applied, AEX delivers sharp peaks, excellent resolution, and robust performance—even for challenging sequences and modifications.</p><p>For laboratories developing or refining oligonucleotide workflows, AEX offers both analytical depth and operational confidence.</p><blockquote><p>If you would like to discuss AEX method development or optimization for oligonucleotides, feel free to contact us at <strong>sales@knauer.net</strong>. More insights into practical oligonucleotide analysis will follow in our <i>“Oligos Made Easy”</i> series.</p><p>For technical questions or in-depth discussion, the author can be reached at <strong>kindler@knauer.net</strong></p></blockquote>

Oligos Made Easy - Part 2: AEX

<p><strong>Although modern agriculture needs to be based on accurate real-time data on soil, plant, and environmental conditions, affordable, sufficiently sensitive, and robust monitoring devices for this purpose are currently missing. According to scientists, low-cost sensors based on new smart materials and printing technologies offer a suitable solution. The results of multidisciplinary research thus far and proposals for the development of these devices have been presented by researchers from Czechia, Great Britain, Spain, and the USA in a review article in the prestigious journal </strong><a target="_blank" rel="noopener noreferrer" href="https://www.nature.com/articles/s41467-026-68778-6#Abs1"><i><strong>Nature Communications</strong></i></a><strong>.</strong></p><p>“<i>Sensor technologies for monitoring plant health are still in their infancy. Only simple sensors capable of monitoring basic parameters such as pH, soil moisture, or temperature are commonly available on the market. However, if farmers are to face current challenges, including climate change, and ensure sufficient food for humanity, they need much more effective tools that will enable them to monitor, for example, various pathogens, including bacteria and fungi. In our opinion, a suitable solution is a combination of new smart materials and printing for the production of inexpensive, durable, and scalable materials</i>,” said the article’s first author, <strong>David Panáček</strong> from CATRIN, who worked on the study during his internship at Imperial College London.</p><p><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/CATRIN_Soucasne_senzory_nestaci_Vedci_navrhuji_novou_cestu_ke_sledovani_zdravi_rostlin_b4014952a3.jpg" alt="CATRIN: David Panáček" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_CATRIN_Soucasne_senzory_nestaci_Vedci_navrhuji_novou_cestu_ke_sledovani_zdravi_rostlin_b4014952a3.jpg 208w," sizes="100vw" width="1536" height="1152"></p><p>Sensors for monitoring plant health, for example, lag behind similar devices used in human medicine. According to the authors, advances in materials science, which will enable the development of scalable sensor technologies, play a key role in this potential shift. “<i>Printing techniques, including inkjet printing, screen printing, aerosol printing, 3D printing, and direct laser writing, offer flexible ways to produce flexible sensors, large-area sensors, and sensors integrated directly into plants. The review article summarizes recent advances in printable low-dimensional materials for agricultural sensors, analyzes their physico-chemical properties in relation to sensor performance, and discusses key challenges and future opportunities requiring interdisciplinary integration</i>,” said one of the corresponding authors, <strong>Michal Otyepka</strong>.</p><p>The research brought together materials scientists, chemists, biologists, sensing experts, and printing technology specialists. Materials research and the use of graphene-based smart materials were led by scientists from CATRIN at Palacký University and VŠB-Technical University of Ostrava. Plant biologists from CATRIN contributed their knowledge of plant development, their responses to stress conditions, and the monitoring of their properties. Researchers from Imperial College London took care of the electronics, while representatives from<a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/companies/36"><strong> CEITEC – VUT</strong></a> focused on printing technologies. The team also included leading experts in sensing from the Catalan Institute of Nanoscience and Nanotechnology in Barcelona, and Joseph Wang of the University of California San Diego, the “father of sensing and electrochemistry,” also contributed his extensive knowledge.</p><p>“<i>This is a groundbreaking study on this topic, which has managed to attract some truly big names in their respective fields. Last but not least, the study demonstrates that interdisciplinarity at CATRIN gives rise to completely new and promising research topics, such as plant sensing and its use for studying plant-environment interactions and smart agriculture,</i>” added another corresponding author, <strong>Nuria De Diego</strong>.</p>

Current sensors are not good enough. Scientists propose a new way to monitor plant health

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The Czech Advanced Technology and Research Institute (CATRIN) at Palacký University is a cutting-edge scientific hub dedicated to advancing research in the fields of nanotechnology, biotechnology, and biomedicine. At its core, CATRIN boasts outstanding scientific teams, featuring international researchers. We emphasize interdisciplinarity, foster global collaborations, and work to translate our research findings into practical applications.

CATRIN

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.

Organomation

Based in Berlin, KNAUER is a medium-sized, owner-managed company that has been serving the sciences since 1962. We develop and manufacture scientific instruments of superior quality for liquid chromatography, including: Analytical HPLC/UHPLC, Preparative HPLC, Fast protein liquid chromatography (FPLC), Multi-column chromatography/Simulated moving bed (SMB) chromatography. High pressure dosing, in-line detection systems, and osmometry are additional business areas.

KNAUER

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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