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 microDAWN™ Multi Angle Light Scattering (MALS) Detector

The microDAWN can be coupled to any UHPLC-SEC system to determine absolute molecular weights and sizes of polymers, peptides, or proteins directly, without resorting to column calibration or reference standards.

<h4>Overview</h4><h5>UHPLC-SEC System</h5>The microDAWN can be coupled to any UHPLC-SEC system to determine absolute molecular weights and sizes of polymers, peptides, or proteins directly, without resorting to column calibration or reference standards. The microDAWN produces minimal band broadening in order to maintain the narrow peaks typical of UHPLC, while meeting or exceeding the sensitivity of the miniDAWN™.<h4>Product Description</h4>The microDAWN MALS detector performs absolute characterization of macromolecules eluting from UHPLC, determining molar mass and size independently of retention time and molecular reference standards. This instrument offers superb sensitivity over a wide range of molar mass, size and concentrations. In most respects the microDAWN is similar to the well-established miniDAWN™, a workhorse MALS instrument used in hundreds of labs around the world for characterizing proteins and other molecules smaller than 50 nm in radius.Distinctly from the miniDAWN, the microDAWN is uniquely suitable for use in conjunction with UHPLC Size Exclusion Chromatography (SEC-MALS) thanks to its small interdetector dispersion. In some cases it may be used with ion-exchange or other types of chromatography. Regardless of the specifics, the microDAWN produces minimal band broadening in order to maintain the narrow peaks typical of UHPLC.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Waters_micro_DAWN_MALS_HPLC_detektor_konfigurace_1_4e888650cf.jpg" alt="Waters microDAWN™ Multi Angle Light Scattering (MALS) Instrument: Experimental setup" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Waters_micro_DAWN_MALS_HPLC_detektor_konfigurace_1_4e888650cf.jpg 229w," sizes="100vw" width="894" height="609"><ul><li>Mw&nbsp; from 200 Da to 10 MDa</li><li>Sensitivity: 1.0 µg/mL BSA (66.4 kDa) in PBS; 50 ng/mL 100 kDa polystyrene in THF.</li><li>Rg &nbsp;from 10 to 50 nm</li><li>Ultra-stable laser</li></ul>The microDAWN and its companion microOptilab™ Refractive Index Detector interface to most standard UHPLC systems. As these detectors are based on the advanced technology of Wyatt's miniDAWN and Optilab™, respectively, users may be confident in the underlying capabilities cited in thousands of peer-reviewed publications.<h5>Ultrasonic Cleaning Included</h5>Each microDAWN includes a COMET™ ultrasonic transducer that cleans MALS flow cells automatically by agitating the fluid and loosening particles from the glass surfaces.<h4>Specifications</h4><h5>Measurement Capabilities</h5><ul><li>Molar Mass Range: From 200 Da to 10 MDa for proteins; up to 1 MDa for linear polymers (Typical, depending on dn/dc, sample concentration, and chromatography conditions)</li><li>Molecular or Particle Size (Radius of Gyration, Rg): 10 nm to 50 nm, extendable up to 150 nm with shape-specific modeling</li><li>Hydrodynamic Radius (Rh):<ul><li>Flow mode: 0.5 nm to 30 nm</li><li>Batch mode: 0.5 nm to 1 µm (Requires WyattQELS™ DLS module or DynaPro™ NanoStar™ with fiber optic connection)</li></ul></li><li>Sensitivity: Detects as little as 3.5 ng of 100 kDa polystyrene in THF or 70 ng of BSA in PBS, assuming use of a 15 cm UHPLC-SEC column with no post-column filter</li></ul><h5>Optical System and Detectors</h5><ul><li>MALS Detectors: Three high-gain photodiodes with broad dynamic range for multi-angle light scattering</li><li>Dynamic Range: 3,300,000:1</li><li>Auxiliary Detectors:<ul><li>Laser monitor for stabilization feedback</li><li>Forward transmission monitor for absorbing samples and data quality assessment</li></ul></li><li>Optional DLS Detection:<ul><li>Integrated WyattQELS™ module within the microDAWN chassis</li><li>External DLS connection via fiber optic from DynaPro™ NanoStar or Mobius™ DLS-ELS instruments</li></ul></li></ul><h5>Laser Specifications</h5><ul><li>Wavelength: 658 nm ± 4 nm</li><li>Power Control: Programmable from 10% to 100%</li></ul><h5>Sample Temperature and Flow Characteristics</h5><ul><li>Sample Temperature: Ambient</li><li>Interdetector Band Broadening:<ul><li>Upstream detector to microDAWN: &lt; 1.5 µL</li><li>Upstream to downstream detector: &lt; 1.6 µL</li></ul></li></ul><h5>Material Compatibility</h5><ul><li>Wetted Materials: 316 stainless steel, fused silica, PEEK, PTFE, and MP35N (iron-free alloy)</li></ul><h5>Electronics and Connectivity</h5><ul><li>Analog Inputs: 2 differential inputs, 24-bit resolution, ±10 V input range</li><li>Analog Outputs: 1 output from a user-selectable measurement channel, ±10 V range</li><li>I/O Ports: Alarm in/out, auto-inject control, Orbit™ valve integration</li><li>Computer Interface: Ethernet</li><li>Data Transmission Rate: Up to 73 Hz</li></ul><h5>User Interface</h5><ul><li>Display: 7” (178 mm) high-resolution multi-touch screen for signal monitoring, instrument settings, and diagnostics</li></ul><h5>Instrument Dimensions</h5><ul><li>Size: 58 cm (L) x 36 cm (W) x 18 cm (H)</li></ul><h4>Other MALS Instruments</h4><ul><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/1114">DAWN™</a> - The most sensitive MALS detector available, anywhere. Incorporates detectors at 18 angles to determine molar masses from 200 Da to 1 GDa and radii from 10 – 500 nm.<ul><li>Standard option: ambient temperature</li><li>Heated/cooled option: -15 °C to +150 °C</li><li>High-temperature option: ambient to +210 °C</li><li>The DAWN offers special options to handle fluorescent samples: fluorescence-blocking filters and an infrared, 785 nm laser.</li></ul></li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/1115">miniDAWN™</a> - Second only to the DAWN in sensitivity. Incorporates detectors at 3 angles to determine molar masses from 200 Da to 10 MDa and radii from 10 – 50 nm. Ambient only.</li><li>ultraDAWN™ - Measures multi-angle light scattering and reports the results – weight-average molecular weight Mw &nbsp;and rms radius Rg &nbsp;– in real time.</li></ul>

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>

Watrex Streamline OLE 200 On-line SPE system

An automatic on-line solid-phase extraction (SPE) and pre-concentration unit with a 10-port selection valve processes up to 7 samples through 7 SPE cartridges. After washing, the eluted components are directed into an HPLC system via a sample valve. 

Automatic on-line SPE/pre-concentration unit equipped with 10 port selection valve for samples and washing solvents, high pressure cartridge selector for 7 cartridges, high pressure pump, and injection valve connected to HPLC instrument.The pump sucks through 10 port selection valve up to 7 samples to 7 SPE cartridges. Then collected components are washed with one or two slushing eluents, and eluted via sample valve into a HPLC system.<img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Watrex_Streamline_OLE_200_On_line_SPE_system_Principle_of_online_SPE_by_OLE_200_e40db78c8f.jpg" alt="Watrex - Watrex Streamline OLE 200 On-line SPE system - Principle of online SPE by OLE 200"><h3>TECHNICAL SPECIFICATION</h3><ul><li>Cartridge selector: twin 10-port high pressure selector, 40MPa</li><li>Cartridge dimensions: 10x4mm</li><li>Connection to HPLC instrument: Rheodyne 6 port sample valve</li><li>Selector: low-pressure 10-port selection valve IDEX</li><li>Sample load pump: high-pressure single piston ss pump</li><li>Instrument control: driver for all valves and pump controll included</li></ul><h3>Ordering information:</h3><h5>PN/Component:</h5><ul><li>D2K2062401 Watrex OLE200</li></ul>You can also visit this product on the <a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/laboratory-automation/streamline-ole-200/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">Watrex website</a>.

Watrex Streamline™ P1 HPLC Pump, Stainless Steel

The Watrex Streamline™ P1 pump is a versatile and powerful dual-piston HPLC pump.

Streamline P1 pump, stainless steel fully meets the demanding requirements for HPLC pumps and can be combined seamlessly with HPLC detectors and instruments from other manufacturers.<blockquote>Price 4 935 € ex VAT</blockquote>In the analytical version of the pump, the flow rate range from 0.001 ml/min to 10 ml/min is adjustable in 1 ul increments with a maximum working pressure of 42 MPa (6,000 psi). Flow rate adjustment accuracy is ±1% and flow rate variation is better than ±0.1%. The pump’s extremely smooth flow profile is ensured by an efficient pulse damper and optimized cam shape.A unique feature is the active piston and seal rinse, which prevents crystallization of buffers. A touch screen display on the front panel allows intuitive control of the pump.The display shows the flow rate, the current pressure and the pump is equipped with pressure limits. A PRIME function is also directly available for flushing at increased flow rates.<figure class="image"><img style="aspect-ratio:611/408;" src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Streamline_P1_Pump_Stainless_Steel_23a7bf9f11.jpg" alt="Watrex: Streamline™ P1 Pump, Stainless Steel." srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Watrex_Streamline_P1_Pump_Stainless_Steel_23a7bf9f11.jpg 234w," sizes="100vw" width="611" height="408"></figure><h3>TECHNICAL SPECIFICATION</h3><ul><li>Flow Rates: 0.001 to 10.000 mL/min</li><li>Pressure: 0 to 6,000 psi (42 MPa)</li><li>Flow precision: &gt; 0.2% RSD</li><li>Flow accuracy: ± 1 % @ 1mL/min and 7 MPa,</li><li>Pressure accuracy: ± 2% of full-scale, with 80:20 H2O/IPA @ 7 MPa</li><li>Pulsation: ± 0.5 % @ 1mL/min and 7 MPa</li><li>Remote inputs: USB</li></ul>You can also visit this product on the <a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/chromatography/pumps/isocratic-pumps/streamline-p1-pump-stainless-steel/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">Watrex website</a>.

Watrex Streamline™ UV1 HPLC detector, Stainless Steel

The Streamline™ UV1 HPLC detector offers an excellent signal-to-noise ratio, making it ideal for demanding applications.

Watrex Streamline™ UV1 programmable UV/VIS detector exhibits excellent signal-to-noise ratio for even the most demanding applications. It is equipped with standard analytical cell. It has a 2-lamp source (deuterium + tungsten), variable wavelength detector configuration suitable for operation between 190 and 800 nm.<blockquote>Price 4 788 € ex VAT</blockquote><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Watrex_Streamline_UV_1_UV_VIS_detector_686c6c9937.jpg" alt="Watrex: Streamline™ UV1 detector, Stainless Steel" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Watrex_Watrex_Streamline_UV_1_UV_VIS_detector_686c6c9937.jpg 245w," sizes="100vw" width="945" height="436"><h3>TECHNICAL SPECIFICATION</h3><ul><li>Light Source: Deuterium Lamp, Tungsten Lamp</li><li>Wavelength Range: 190 – 800 nm</li><li>Baseline Noise: 1 x 10-5 AU (@240 nm, 2 sec. risetime)</li><li>Baseline Drift: better than 3 x 10-4 AU/h</li><li>Wavelenghth Reproducibility: ± 0.1 nm</li><li>Linearity: better than 2.5 AU</li><li>Analog Output: 1x 1 V</li></ul>You can also visit this product on the <a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/chromatography/detectors/uv-vis-detectors/streamline-uv1-detector/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">Watrex website</a>.

Watrex Streamline™ PDA1 HPLC Detector, Stainless Steel

Photo-diode-array (PDA) HPLC detector with the optimum wavelength can be selected for each analyzed substance.

Watrex Streamline™ PDA1 is a photo-diode-array (PDA) detector for routine analysis and sophisticated research.<blockquote>Price 9 972 € ex VAT</blockquote>The dual lamp design offers a wavelength range of 190 – 720 nm (256 Diodes) with a low baseline noise.The front-accessible flow cell can easily bHPLCe exchanged, as can be the lamps which are accessible through a side panel in the instrument housing.Streamline™ PDA1 features 4-Wavelength channels to measure chromatograms at 4 different wavelengths at the same time. With this feature the optimum wavelength can be selected for each analyzed substance.<figure class="image"><img style="aspect-ratio:945/435;" src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Watrex_Streamline_PDA_1_Photodiode_array_detector_3784ec588b.jpg" alt="Watrex: Streamline™ PDA1 Detector, Stainless Steel" srcset="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/thumbnail_Watrex_Watrex_Streamline_PDA_1_Photodiode_array_detector_3784ec588b.jpg 245w," sizes="100vw" width="945" height="435"></figure><h3>TECHNICAL SPECIFICATION</h3><ul><li>Wetted Materials: Stainless Steel/ PEEK*, teflon, Glass (*depending on configuration)</li><li>Light Source: Deuterium Lamp, Tungsten Lamp</li><li>Wavelength Range: 190 – 720 nm</li><li>Number of Diodes: 256</li><li>Baseline Noise: ± 1 x 10-5 AU (@240 nm, 1 sec. risetime)</li><li>Baseline Drift: better than 3 x 10-4 AU/h</li><li>Wavelength Accuracy: 0.5 nm</li><li>Mean Pixel Pitch: 2.2 nm</li><li>Resolution: 7 nm</li><li>Linearity: higher than 2.0 AU</li><li>Data Rate: 1 Hz – 100 Hz</li></ul>You can also visit this product on the <a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/chromatography/detectors/uv-vis-detectors/streamline-pda1-detector-256-diodes/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">Watrex website</a>.

Watrex Streamline RI1 Refractive index HPLC detector

The Watrex Streamline RI1 Refractive Index Detector is an essential component in high-performance liquid chromatography (HPLC) systems.

Streamline™ RI1 refractive index detector is suitable for detecting compounds with little or no UV activity such as alcohols, sugars, lipids or polymers. This instrument is designed for use in analytical HPLC (high performance liquid chromatography) as well as for GPC (gel permeation chromatography) applications.<h3>FEATURES</h3><ul><li>Advanced temperature control for high sensitivity and reproducibility</li><li>Prime purge valve</li><li>Long-life LED light source</li><li>Pressure resistant flow cell</li></ul><h3>TECHNICAL SPECIFICATION</h3><ul><li>Light Source: Long-life LED</li><li>Refractive index Range: 1.00 - 1.75 RIU</li><li>Baseline Noise: ± 2.5 nRIU</li><li>Baseline Drift: 200 nRIU/h</li><li>Linearity: &gt; 1000 μRIU</li><li>Flow cell pressure resistance: 5 bar</li><li>Flow cell volume: 15 μl</li><li>Time constant: 0.00/0.01/0.02/0.05/0.1/0.2/0.5/1.0/2.0/5.0/10.0 s</li><li>Analog Output: 1x 0-2.5V</li><li>Outputs: Event 1, Start (OUT), Error (OUT), + 5 V, 24 V Valve</li></ul><h3>Ordering information:</h3><h5>PN/Component:</h5><ul><li>SRI101-001 Watrex Streamline™ RI refractive index detector (Price 7 018 € ex VAT)</li></ul>You can also visit this product on the <a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/chromatography/detectors/other-hplc-detectors/streamline-ri1-detector/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">Watrex website</a>.

Watrex Streamline VD1 Viscosimetric HPLC detector

 Watrex Streamline™ VD1 viscosimetric detector is designed for detailed characterization of polymer compounds in both aqueous and organic solvents.

Streamline™ VD1 viscosimetric detector measures absolute intrinsic viscosity and is ideal as a detector for online monitoring in any GPC system. VD1 enables measurement of absolute molecular size using Wheatstone bridge operating principle.<h3>FEATURES</h3><ul><li>High sensitivity and stability</li><li>Low-noise</li><li>Open protocol digital data format</li><li>Direct dual analog output</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Watrex_Streamline_VD_1_Viscosimetric_detector_Universal_calibration_from_VD_1_data_1_149c741933.jpg" alt="Watrex: Watrex Streamline VD1 Viscosimetric detector - Universal calibration from VD1 data 1"><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Watrex_Streamline_VD_1_Viscosimetric_detector_Universal_calibration_from_VD_1_data_2_a616c498e8.jpg" alt="Watrex: Watrex Streamline VD1 Viscosimetric detector - Universal calibration from VD1 data 2"><h3>TECHNICAL SPECIFICATION</h3><ul><li>Wavelength Range: 190 – 720 nm</li><li>Baseline Noise: ± 1 x 10-5 AU (@240 nm, 2 sec. risetime)</li><li>Baseline Drift: &lt; 3 x 10-4 AU/h</li><li>Wavelength Accuracy: ± 0.5 nm</li><li>Wavelenghth Reproducibility: ± 0.1 nm</li><li>Mean Pixel Pitch: 2.2 nm</li><li>Resolution (λ FWHM): 7 nm</li><li>Linearity: &gt; 2.5 AU</li><li>Wavelength Program: Programmable, 10 steps</li><li>Analog Output (optional): 1x 1 V</li><li>Options: Dual channel configuration, thermostated flow cell</li></ul><img src="https://storage.googleapis.com/labrulez-bucket-strapi-h3hsga3/Watrex_Watrex_Streamline_VD_1_Viscosimetric_detector_Technical_specification_76756715f6.jpg" alt="Watrex: Watrex Streamline VD1 Viscosimetric detector - Technical specification"><h3>Ordering information:</h3><h5>PN/Component:</h5><ul><li>SVD101-001 Watrex Streamline™ VD1 viscosimetric detector (Price 19 741 € ex VAT)</li></ul>You can also visit this product on the <a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/chromatography/detectors/other-hplc-detectors/streamline-vd1-detector/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">Watrex website</a>.

Watrex Streamline CT1/CT1i HPLC Column thermostat

Watrex Streamline™ CT1i column thermostat is an ideal tool for maintaining stable separation temperatures.

Watrex Streamline CT1/CT1i column thermostat is an ideal tool to grant stable separation temperature even if laboratory temperature fluctuates during the day. It is also essential instrument in sugar analysis and/or many applications requiring higher column temperature. An optional built-in manual syringe front loaded sample injector increases usage comfort.<h3>FEATURES</h3><ul><li>Excellent temperature stability</li><li>Heating up to 100°C</li><li>Thermal fuse against overheating</li><li>Up to 3 columns with length of 250 mm can be placed in the thermostat</li><li>Color touch panel control</li><li>Possibility of installing manual injection valve</li></ul><h3>TECHNICAL SPECIFICATION</h3><ul><li>Temperature range: 10 °C above ambient temperature to 100 °C</li><li>Temperature accuracy: max. 0,5 % of actual temperature</li><li>Temperature stability: RSD &lt; 0,4 %</li><li>Settability: 0,1 °C</li><li>Internal dimensions: 320 x 50 x 30 mm (L x W x H)</li><li>Compartment material: PTFE coated metal</li><li>Compartment connection: USB</li><li>Control: build-in color touch panel, datasystem</li></ul><h3>Ordering information:</h3><h5>PN/Component:</h5><ul><li>ST101-001 Streamline CT1 Columm Thermostat (Price 1 720 € ex VAT)</li><li>ST101-002 Streamline CT1i Columm Thermostat with manual injector</li></ul>You can also visit this product on the <a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/chromatography/column-thermostats/streamline-ct1-columm-thermostat/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">Watrex website</a>.

Watrex Streamline GPC system

GPC system is an isocratic HPLC system consisting of one P1 pump, CT1i column thermostat with manual injector and RI1 refractive index detector.

GPC system is an isocratic HPLC system consisting of one P1 pump, CT1i column thermostat with manual injector and RI1 refractive index detector.<h3>FEATURES</h3><ul><li>Optimized pump mechanics of P1 pump with parallel piston design offers excellent flow rate accuracy and low RI signal pulsation.</li><li>The thermal isolated optic with a counter-current heat exchanger and programmable temperature control, results in an extremly stable baseline and an optimal Signal/Noise ratio od RI1.</li><li>The system can be upgraded with autosampler and fraction collector, or VD 400 Viscometer Detector.</li><li>Data acquisition, processing and instrument control is done by Clarity Chromatography Station with GPC option or Agilent TriSEC software.</li></ul><h3>TECHNICAL SPECIFICATION</h3><ul><li><a target="_blank" rel="noopener noreferrer" href="https://watrex.com/?s=streamline+p1+pump&amp;post_type=product&amp;dgwt_wcas=1?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">P1 HPLC pump: Flow Rates</a></li><li><a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/chromatography/detectors/other-hplc-detectors/streamline-ri1-detector/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">RI1 refractive index detector</a></li><li><a target="_blank" rel="noopener noreferrer" href="https://watrex.com/obchod/chromatography/column-thermostats/streamline-ct1-columm-thermostat/?utm_source=labrulez&amp;utm_medium=propagace&amp;utm_campaign=labrulez_produkty">CT1 Column thermostat</a></li><li><a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/999">Clarity™ Chromatography Station</a></li></ul><h5>COMPONENT SPECIFICATION - P1 HPLC pump: Flow Rates</h5><ul><li>Flow Rates: 0.001 to 10.000 mL/min</li><li>Pressure: 0 to 6,000 psi (42 MPa)</li><li>Flow precision: &gt; 0.2% RSD</li><li>Flow accuracy: ± 1 % @ 1mL/min and 7 MPa,</li><li>Pressure accuracy: ± 2% of full-scale, with 80:20 H2O/IPA @ 7 MPa</li><li>Pulsation: ± 0.5 % @ 1mL/min and 7 MPa</li><li>Remote inputs: USB</li></ul><h5>COMPONENT SPECIFICATION - RI1 refractive index detector</h5><ul><li>Light Source: Long-life LED</li><li>Refractive index Range: 1.00 - 1.75 RIU</li><li>Baseline Noise: ± 2.5 nRIU</li><li>Baseline Drift: 200 nRIU/h</li><li>Linearity: &gt; 1000 μRIU</li><li>Flow cell pressure resistance: 5 bar</li><li>Flow cell volume: 15 μl</li><li>Time constant: 0.00/0.01/0.02/0.05/0.1/0.2/0.5/1.0/2.0/5.0/10.0 s</li><li>Analog Output: 1x 0-2.5V</li><li>Outputs: Event 1, Start (OUT), Error (OUT), + 5 V, 24 V Valve</li></ul><h5>COMPONENT SPECIFICATIONS - CT1 Column thermostat</h5><ul><li>Temperature range: 10 °C above ambient temperature to 100 °C</li><li>Temperature accuracy: max. 0,5 % of actual temperature</li><li>Temperature stability: RSD &lt; 0,4 %</li><li>Settability: 0,1 °C</li><li>Internal dimensions: 320 x 50 x 30 mm (L x W x H)</li><li>Compartment material: PTFE coated metal</li><li>Compartment connection: USB</li><li>Control: build-in color touch panel, datasystem</li></ul><h5>COMPONENT SPECIFICATIONS - <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/999">Clarity™ Chromatography Station:</a></h5>Advanced chromatographic datastation for data acquisition and evaluation supported with <a target="_blank" rel="noopener noreferrer" href="https://lcms.labrulez.com/products/1004">GPC module for MWD, Mw, Mn, Mz calculation</a>. Enables rutine separations with pre-set methods, containing all experimental and conditions and data evaluation settings. PC Win 10 Professional with LCD monitor included.<h3>Ordering information:</h3><h5>PN/Component:</h5><ul><li>SGPC01-001 Streamline™ manual GPC system with Refractive index detector (Includes P1 pump, RI1 detector, CT1i column thermostat with manual injector, solvent rack, Clarity PC station)</li></ul>Optional configurations:<ul><li>ST99-002 Remove CT1i column thermostat with manual injector from system</li><li>SAS90-001 Add AS1 Autosampler to system</li><li>SFC90-001 Add FC1 Fraction collector to system</li></ul>

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