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

<h3>Charged for Action: The Hidden Secrets of AEX Oligonucleotide Analysis</h3>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.<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">Among the analytical techniques available today, anion exchange chromatography (AEX) 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.<blockquote><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/article/6808">Part 1 of the Oligos series: A Practical Guide to Oligonucleotide Production – From Concept to Final Product</a></blockquote><h4>How Scientists Read Oligonucleotides Using Charge</h4>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.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.<h4>Why Ion Exchange Works: Binding, Retention, and Release</h4>Ion exchange chromatography (IEX) relies on electrostatic interactions between analytes and a charged stationary phase. In the case of oligonucleotides, anion exchange is used, where negatively charged molecules interact with positively charged functional groups on the resin—most commonly quaternary amines.The system consists of two main components:<ul><li>Stationary phase: A positively charged resin that binds anionic analytes.</li><li>Mobile phase: An aqueous buffer system, typically combined with a salt gradient, that controls both pH and elution strength.</li></ul>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.<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"><h4>The Five-Step Workflow of Ion Exchange Chromatography</h4>AEX separations generally follow a well-established sequence of steps:<ol><li>Column equilibration 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>Sample loading 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>Washing 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>Elution 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>Regeneration and re-equilibration 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><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"><h4>Why AEX Is Especially Effective for Oligonucleotides</h4>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.Key factors influencing AEX behavior include:<ul><li>Charge density: Longer oligonucleotides carry more negative charges and therefore exhibit stronger retention.</li><li>Resin chemistry: Strong and weak anion exchangers differ in functional groups and pH stability, influencing selectivity and robustness.</li><li>Buffer composition: The choice of buffering ions and salt gradients directly affects elution strength and resolution.</li></ul>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.<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"><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"><h4>AEX as the Gold Standard for Oligonucleotide Separation</h4>Anion exchange chromatography has become the method of choice for both analytical and preparative oligonucleotide workflows. Its advantages include:<ul><li>High resolving power: Closely related impurities, including n–1 or n–2 species, can often be separated and quantified.</li><li>Predictable retention behavior: In many cases, retention time correlates linearly with oligonucleotide length, simplifying identification.</li><li>Compatibility with modified oligonucleotides: Even chemically modified sequences retain their anionic nature, allowing AEX to resolve both products and related impurities.</li><li>Excellent control via gradient elution: Salt gradients provide precise tuning of selectivity and resolution.</li></ul>Typically, shorter or degraded oligonucleotides elute at lower ionic strength, while full-length products with higher charge density appear later in the chromatogram.<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"><h4>Final Perspective: Mastering AEX with Confidence</h4>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.For laboratories developing or refining oligonucleotide workflows, AEX offers both analytical depth and operational confidence.<blockquote>If you would like to discuss AEX method development or optimization for oligonucleotides, feel free to contact us at sales@knauer.net. More insights into practical oligonucleotide analysis will follow in our “Oligos Made Easy” series.For technical questions or in-depth discussion, the author can be reached at kindler@knauer.net</blockquote>

Oligos Made Easy - Part 2: AEX

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 <a target="_blank" rel="noopener noreferrer" href="https://www.nature.com/articles/s41467-026-68778-6#Abs1">Nature Communications</a>.“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,” said the article’s first author, David Panáček from CATRIN, who worked on the study during his internship at Imperial College London.<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">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. “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,” said one of the corresponding authors, Michal Otyepka.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"> CEITEC – VUT</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.“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,” added another corresponding author, Nuria De Diego.

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/Wyatt ViscoStar HPLC viscometer

Waters ViscoStar is a highly sensitive, on-line differential viscometer used in conjunction with SEC-MALS-IV to determine the size and conformation of all types of biopolymers, synthetic polymers and even proteins and peptides.

<h4>Highly Sensitive</h4>A highly sensitive, on-line differential viscometer used in conjunction with SEC-MALS-IV to determine the size and conformation of all types of biopolymers, synthetic polymers and even proteins and peptides.<h4>Multiple Novel Technologies</h4>The ViscoStar incorporates multiple novel technologies to provide the highest sensitivity, stability and solvent compatibility of any available viscometer for GPC. Its ease-of-use and serviceability make it the perfect companion for Wyatt's DAWN™ light scattering and Optilab™ refractive index detectors.<h4>Another path to polymer and protein characterization: SEC-MALS-IV</h4>When coupled with size-exclusion chromatography and a concentration detector such as the Optilab™ , the ViscoStar derives the intrinsic viscosity (IV) of polymers. An inherently valuable physico-chemical property in itself, IV is best utilized together with molar mass information from multi-angle light scattering (SEC-MALS-IV) to derive the hydrodynamic radius, conformation, and branching ratio of a macromolecule in solution.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Visco_Star_pump_pulse_suppression_with_inset_e8c2fbfc18.jpg" alt="Waters ViscoStar: Patented pulse compensation technology in the ViscoStar eliminates pump fluctuations. At the hardware level, the bridge is impedance matched for dynamic balance, greatly reducing the effect of pump pulses. An additional layer of software filtering eliminates residual pump pulses." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Visco_Star_pump_pulse_suppression_with_inset_e8c2fbfc18.jpg 233w," sizes="100vw" width="348" height="233"><h5>Key benefits of the ViscoStar</h5><ul><li>High sensitivity, equivalent to 100 ng of 100 kDa polystyrene in THF at 1.0 mL/min injected onto a standard GPC column</li><li>High dynamic range of over 135,000:1. The full measurement range corresponds to over 13 mg/mL of 100 kDa polystyrene in THF</li><li>Extended solvent compatibility with all-316 stainless steel transducers</li><li>Temperature range from 4 °C to 70 °C for polymers or proteins that require a range of temperatures</li><li>Minimal band broadening thanks to fast pressure transducers</li><li>Pump pulse suppression to below 4 Pa (hardware alone) or 1 Pa (hardware + software) without loss of chromatographic resolution</li><li>Automated capillary bridge tuning with no moving parts, to guarantee a perfectly balanced bridge, every run</li><li>Enhanced thermal stability with drift of &lt;2.5 Pa/hour</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Visco_Star_cmc_plga_intrinsic_viscosity_graphs_be99c5d115.jpg" alt="Waters ViscoStar: The ViscoStar provides the highest available dynamic range and sensitivity in online viscometry. This graph shows the intrinsic viscosities of 1) poly(lactic co-glycolic acid), or PLGA, in THF and 2) carboxymethyl cellulose, or CMC, in aqueous mobile phase, both measured with a ViscoStar and Optilab, spanning a range from tens to thousands of mL/g. The same instruments readily measure intrinsic viscosity values in the low single digits with excellent signal-to-noise, even at very low concentrations." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Visco_Star_cmc_plga_intrinsic_viscosity_graphs_be99c5d115.jpg 236w," sizes="100vw" width="406" height="268"><h5>SEC-IV without MALS?</h5>Yes, as much as we love MALS for optimal polymer analysis, it's true that there are occasions when it just won't fit the bill.Universal calibration is a parallel technique to SEC-MALS for determining molecular weight, commonly used to characterize linear polymers. While universal calibration overcomes some of the problematic issues associated with column calibration by reference molecules, it does not account for non-ideal column behavior caused by chemical solute-column interactions or hyperbranching.Universal calibration is particularly-well suited to replace MALS for:<ul><li>Strongly fluorescent polymers, in particular those not adequately addressed by a DAWN™ with long-wavelength (785 nm) laser or a standard DAWN (685 nm) with fluorescence-blocking filters.</li><li>Weakly-scattering polymer/solvent systems with very low dn/dc values</li></ul>The Mark-Houwink-Sakurada relationship makes use of empirical relationships between intrinsic viscosity and molar mass, specific to each polymer and solvent, to estimate molar mass from SEC-IV measurements. Of course, the best way to determine MHS coefficients is to measure them using SEC-MALS-IV and ASTRA™!<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Visco_Star_v3_protein_rh_measurements_0951d3769a.jpg" alt="Waters ViscoStar: Three IgG proteins with similar MWs eluted at different elution volumes. To understand their different elution properties, online DLS is typically used to measure the hydrodynamic radius, R h , of a protein. However, online DLS did not provide reliable insights, in this case due to the relatively high experimental uncertainty of the DLS. The precise Rh values obtained with a MALS detector and the ViscoStar III, on the other hand, clearly revealed the causes. IgG B eluted later than IgG A due to its more compact structure; IgG C had a slight interaction with the SEC column." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Visco_Star_v3_protein_rh_measurements_0951d3769a.jpg 237w," sizes="100vw" width="401" height="264"><h4>Specifications</h4><h5>Measurement Capabilities – Differential Viscosity</h5><ul><li>Sensitivity: Detects as little as 0.1 µg of 100 kDa polystyrene in THF at 1 mL/min under typical GPC conditions.</li><li>Differential Pressure Performance:<ul><li>Noise: &lt; 0.05 Pa</li><li>Range: 6.9 kPa, with built-in overpressure protection</li><li>Drift: &lt; 2.5 Pa/hr</li><li>Linearity: Within 0.5% of full scale</li><li>Dynamic Range: 135,000:1</li></ul></li><li>Capillary Bridge Autobalance: Thermally regulated, leak-free mechanism ensures stable baseline and precision.</li><li>Sample Shear Rate: Up to 5000 Hz with water at 1 mL/min</li></ul><h5>Fluidics and Flow Compatibility</h5><ul><li>Maximum Flow Rate:<ul><li>Aqueous: 1.5 mL/min</li><li>THF: 3 mL/min</li></ul></li><li>Delay Volume Options: Configurable at 16.2, 10.8, or 5.4 mL; optional factory-installed upgrade to 32.4 mL (Note: actual column fluid volume is approx. half the listed value)</li><li>Maximum Inlet-to-Outlet Pressure: 690 kPa</li><li>Wetted Materials: 316 stainless steel, PTFE, zirconium silicate, Kalrez, Inconel, and 26-1 stainless steel – all selected for chemical resistance and long-term durability</li></ul><h5>Temperature Control</h5><ul><li>Operating Range: 4 °C to 70 °C</li><li>Stability: Maintains temperature within &lt; 0.005 °C for precise measurements</li><li>Ambient Conditions: 0 °C to 40 °C; relative humidity 20% to 70%</li></ul><h5>Electronics and Connectivity</h5><ul><li>Digital Output: 20-bit resolution at 10 Hz for high-fidelity data</li><li>Auxiliary I/O:<ul><li>Inputs: Autoinject contact closure, Alarm In, and 2 analog inputs (18-bit, ±10 V)</li><li>Outputs: Autoinject retransmit, Alarm Out, Recycle Out</li></ul></li><li>Communication Interface: Ethernet for seamless integration into lab networks and data systems</li></ul><h5>User Interface</h5><ul><li>Front Panel Display: 7” (178 mm) high-resolution capacitive touchscreen for monitoring signals, diagnostics, and adjusting settings with ease</li></ul><h5>Instrument Dimensions</h5><ul><li>Size: 58 cm (L) × 36 cm (W) × 18 cm (H)</li></ul><h4>Other Viscometers</h4><ul><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/1267">microViscoStar™ </a>- Similar to the ViscoStar but designed specifically for use with UHPLC/APC.</li></ul>

Waters/Wyatt microViscoStar viscometer

The Waters microViscoStar incorporates multiple novel technologies to provide the highest sensitivity, stability and solvent compatibility of any available viscometer for UHPLC. 

<h4>Highly Sensitive</h4>A highly sensitive, on-line differential viscometer used with SEC-MALS-IV to determine the size and conformation of polymers, proteins and peptides separated by UHPLC.<h4>Multiple Novel Technologies</h4>The microViscoStar™ incorporates multiple novel technologies to provide the highest sensitivity, stability and solvent compatibility of any available viscometer for UHPLC. Its ease-of-use and serviceability make it the perfect companion for Wyatt's microDAWN™ light scattering and microOptilab™ refractive index detectors for UHPLC.<h4>Another path to polymer and protein characterization: SEC-MALS-IV</h4>When coupled with size-exclusion chromatography and a concentration detector such as the Optilab™ , the microViscoStar derives the intrinsic viscosity (IV) of polymers. An inherently valuable physico-chemical property in itself, IV is best utilized together with molar mass information from multi-angle light scattering (SEC-MALS-IV) to derive the hydrodynamic radius, conformation, and branching ratio of a macromolecule in solution.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_Visco_Star_pump_pulse_suppression_with_inset_e8c2fbfc18.jpg" alt="Waters microViscoStar: Patented pulse compensation technology in the microViscoStar eliminates pump fluctuations. At the hardware level, the bridge is impedance-matched for dynamic balance, greatly reducing the effect of pump pulses. An additional layer of software filtering eliminates residual pump pulses." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_Visco_Star_pump_pulse_suppression_with_inset_e8c2fbfc18.jpg 233w," sizes="100vw" width="348" height="233"><h5>Key benefits of the ViscoStar</h5><ul><li>High sensitivity, equivalent to 5 ng of 100 kDa polystyrene in THF at 1.0 mL/min injected onto a standard GPC column</li><li>High dynamic range of over 135,000:1. The full measurement range corresponds to over 13 mg/mL of 100 kDa polystyrene in THF</li><li>Extended solvent compatibility with all-316 stainless steel transducers</li><li>Temperature range from 4 °C to 70 °C for polymers or proteins that require a range of temperatures</li><li>Minimal band broadening thanks to fast pressure transducers</li><li>Pump pulse suppression to below 4 Pa (hardware alone) or 1 Pa (hardware + software) without loss of chromatographic resolution</li><li>Automated capillary bridge tuning with no moving parts, to guarantee a perfectly balanced bridge, every run</li><li>Enhanced thermal stability with drift of &lt;1.25 Pa/hour</li></ul><h4>SEC-IV without MALS?</h4>Yes, as much as we love MALS for optimal polymer analysis, it's true that there are occasions when it just won't fit the bill.Universal calibration is a parallel technique to SEC-MALS for determining molecular weight, commonly used to characterize linear polymers. While universal calibration overcomes some of the problematic issues associated with column calibration by reference molecules, it does not account for non-ideal column behavior caused by chemical solute-column interactions or hyperbranching.Universal calibration is particularly-well suited to replace MALS for:<ul><li>Strongly fluorescent polymers</li><li>Weakly-scattering polymer/solvent systems with very low dn/dc values</li></ul>The Mark-Houwink-Sakurada relationship makes use of empirical relationships between intrinsic viscosity and molar mass, specific to each polymer and solvent, to estimate molar mass from SEC-IV measurements. Of course, the best way to determine MHS coefficients is to measure them using SEC-MALS-IV and ASTRA™<h4>Specifications</h4><h5>Measurement Capabilities – Differential Viscosity</h5><ul><li>Sensitivity: Detects as little as 5 ng of 100 kDa polystyrene in THF at 1 mL/min under typical UHPLC-SEC conditions.</li><li>Differential Pressure Performance:<ul><li>Noise: &lt; 0.05 Pa</li><li>Range: Up to 6.9 kPa, with overpressure protection</li><li>Drift: &lt; 1.25 Pa/hr</li><li>Linearity: Within 0.5% of full scale</li><li>Dynamic Range: 135,000:1</li></ul></li><li>Capillary Bridge Autobalance: Thermal, leak-free mechanism ensures stable baseline performance.</li><li>Sample Shear Rate: Up to 15,000 Hz with water at 1 mL/min for high-resolution viscosity profiling.</li></ul><h5>Fluidics and Compatibility</h5><ul><li>Maximum Flow Rate: Aqueous and THF: up to 1 mL/min (Note: Using an inline UV detector may reduce allowable flow rate.)</li><li>Delay Volume: 5.4 mL</li><li>Maximum Inlet-to-Outlet Pressure: 3000 kPa (435 psi)</li><li>Wetted Materials: 316 stainless steel, PTFE, zirconium silicate, Kalrez®, Inconel, 26-1 stainless steel, and nickel</li></ul><blockquote>Note: Due to the location of wetted components, this instrument is primarily recommended for use with organic solvents. High-ionic-strength buffers may cause corrosion.</blockquote><h5>Temperature Control</h5><ul><li>Operating Range: 4 °C to 70 °C</li><li>Stability: Maintains temperature within &lt; 0.005 °C</li><li>Ambient Conditions: 0 °C to 40 °C; 20% to 70% relative humidity</li></ul><h5>Electronics and Connectivity</h5><ul><li>Digital Output: 20-bit resolution at 10 Hz</li><li>Auxiliary I/O:<ul><li>Inputs: Autoinject contact closure, Alarm In, and 2 analog inputs (16-bit, ±10 V)</li><li>Outputs: Autoinject retransmit, Alarm Out, Recycle Out</li></ul></li><li>Communication Interface: Ethernet</li></ul><h5>User Interface</h5><ul><li>Front Panel Display: 7” (178 mm) high-resolution, capacitive multi-touch screen for real-time monitoring, configuration, and diagnostics</li></ul><h5>Instrument Dimensions</h5><ul><li>Size: 60 cm (L) × 36 cm (W) × 17 cm (H)</li></ul><h4>Other Viscometers</h4><ul><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/1117">ViscoStar™</a> - A highly sensitive, on-line differential viscometer used in conjunction with SEC-MALS to determine the size and conformation of all types of biopolymers, synthetic polymers and even proteins and peptides.</li><li>The ViscoStar incorporates multiple novel technologies to provide the highest sensitivity, stability and solvent compatibility of any available viscometer for GPC. Its ease-of-use and serviceability make it the perfect companion for Wyatt's DAWN® light scattering and Optilab® refractive index detectors. Temperature-controlled from 4 °C to 70 °C .</li></ul>

Products from category Viscometer detector from Waters - page 1

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