ARTICLES

1% Abweichung, 40% Fehler: So htig ist Durchflussmessung

Kalibrierungen sind Pflicht für wiederholgenaue Ergebnisse. Doch gerade aufwendige Messreihen wie in der Gel-Permeations-Chromatographie dauern oft lange, sodass die tatsächliche Flussrate minimal abweichen kann. Welch enorme Folgen dies nach sich zieht, zeigt das folgende Beispiel.
Published in LaborPraxis – April 2025
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Effects of small deviations in flow rate on GPC/SEC results

GPC/SEC is undoubtedly one of the most powerful techniques for the characterisation of natural and synthetic polymers. Its fexibility and the high information content available from just a single measurement, makes it the technique of choice for simple determination of molecular weight distribution and polydispersity of the most complex structure analysis or co-polymer composition distributions.
Published in Lab Asia – April 2025
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El refractómetro differencial mejora la determinación del peso molecular por dispersión de la luz

El refractómetro differencial de Testa Analytical mejora la precisión de la determinación de dn/dc utilizando técnicas de dispersión de luz.
Published in International Labmate – March 2025
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Effects of small deviations in flowrate on GPC/SEC results

GPC/SEC is undoubtedly one of the most powerful techniques for the characterisation of natural and synthetic polymers. Its fexibility and the high information content available from just a single measurement, makes it the technique of choice for simple determination of molecular weight distribution and polydispersity to the most complex structure analysis or co-polymer composition distribution.
Published in International Labmate – March 2025
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Comparing volumetric and thermal flowmeters for assessing and validating liquid chromatography performance

Assessing and validating the performance of a pump serving HPLC, UHPLC, Ion Chromatography of GPC/SEC system is a crucial task in many laboratories these days.
Published in International Labmate – February 2025
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Comparing volumetric and thermal flowmeters for assessing and validating liquid chromatography performance

Assessing and validating the performance of a pump serving HPLC, UHPLC, Ion Chromatography of GPC/SEC system is a crucial task in many laboratories these days.
Published in Lab Asia – February 2025
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Comparaison des débitmètres volumétriques et thermiques pour l'évaluation et la validation des performances de la chromatographie liquide

L’évaluation et la validation des performances d’une pompe destinée aux systèmes HPLC, UHPLC, de chromatographie ionique ou de GPC/SEC est une tâche cruciale dans de nombreux laboratoires.
Published in La Gazette du Laboratoire – December 2024
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Comparación de caudalímetros volumétricos y térmicos para evaluary y validar el rendimiento de la cromatografía líquida

Evaluar y validar el rendimiento de una bomba al servicio de un sistema de HPLC, UHPLC, cromatografía iónica o GPC/SEC es una tarea crucial en muchos laboratorios hoy en día. Para ello, la determinación precisa del caudal es una herramienta poderosa.
Published in Tecnicas de Laboratorio – December 2024
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Testa Analytical's monitoring device used to validate preparative HPLC pump

Regular pump flow rate validation is crucial to ensuring pump performance, repeatability, and compliance with regulations. In this investigation, a non-invasive, real time flow monitoring device – the Prep Flowmeter was used to validate a Teledyne SSI M1 40ml single-headed, positive displacement piston pump commonly used for preparative liquid chromatography applications.
Published in Scientist Live – December 2024
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Validation du gradient HPLC à l'aide de débitmètres non invasifs

La CLHP à gradient est un outil essentiel pour l’analyse d’échantillons contenant des composés de polarité variable. Son efficacité découle de la possibilité d’adapter à la fois la durée et la composition du gradient, ce qui permet de manipuler les temps de rétention des analytes.
Published in La Gazette du Laboratoire – October 2024
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HPLC gradient validation using non-invasive flowmeters

Gradient HPLC serves as a crucial tool for analysing samples containing compounds with varying polarity. Its effectiveness stems from the ability to tailor both gradient time and composition, enabling the manipulation of analyte retention times. However, challenges arise from deviations in the programmed gradient profiles produced by HPLC systems, impacting retention time and peak shape. Several factors contribute to this variability in gradient HPLC, such as solvent quality, pump performance, changes in system pressure, and the condition of the columns. Addressing these challenges requires precise control and monitoring of gradient profiles.
Published in International Labmate – September 2024
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Validación de gradientes de HPLC con caudalímetros no invasivos

La HPLC de gradiente es una herramienta crucial para analizar muestras que contienen compuestos de polaridad variable. Su eficacia radica en la capacidad de adaptar tanto el tiempo como la composición del gradiente, lo que permite manipular los tiempos de retención de los analitos.
Published in Tecnicas de Laboratorio – July/August 2024
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Enhancing HPLC Field Service with fast-response, non-invasive flowmeters

Field Service Engineers are crucial to scientists striving to get the most from their analytical equipment. The maintenance, performance assurance and validation of HPLC/uHPLC systems gains particular importance when this equipment is an essential component in labs subject to compliance found in the pharmaceutical, food, beverage, and environmental analysis sectors.
Published in Lab Asia – June 2024
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Enhancing HPLC Field Service with fast-response, non-invasive flowmeters

Field Service Engineers are crucial to scientists striving to get the most from their analytical equipment. The maintenance, performance assurance and validation of HPLC/UHPLC systems gains particular importance when this equipment is an essential component in labs subject to compliance found in the pharmaceutical, food, beverage, and environmental analysis sectors.
Published in MicroBioz India – April 2024
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Mejora del servicio de campo de HPLC con caudalímetros no invasivos y de respuesta rápida

Field Service Engineers are crucial to scientists striving to get the most from their analytical equipment. The maintenance, performance assurance and validation of HPLC/UHPLC systems gains particular importance when this equipment is an essential component in labs subject to compliance found in the pharmaceutical, food, beverage, and environmental analysis sectors.
Published in Laboratorio – April 2024
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Laboratory 4.0 & Liquid Chromatography

In the world of analytical chemistry, liquid chromatography stands as a cornerstone technique, enabling scientists to separate, identify, and quantify components with unparalleled precision.
Published in MicroBioz India – February 2024
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Studying the Impact of Dissolved and Undissolved Gas on the Performance of Peristaltic Pumps

A set of experiments illustrating how dissolved gas can affect peristaltic pumps in chromatography processes.
Published in Lab Manager – July 2023
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Gefahr erkannt, Gefahr gebannt

Der Feind peristaltischer Pumpen sind Gasblasen. Welchen Einfluss gelöstes und ungelöstes Gas auf die Leistung dieser Pumpen hat und damit auf HPLC, GPC & Co. und was sich dagegen unternehmen lässt, erfahren Sie in diesem Beitrag.
Published in Laborpraxis – May-June 2023
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Studying the Impact of Dissolved and Undissolved Gas on the Performance of Peristaltic Pumps

Peristaltic pumps are fluid delivery tools widely used in laboratory techniques including HPLC, GPC/SEC, Flow Chemistry and Liquid Dosing. It is widely acknowledged that dissolved gas can have an impact on the performance of peristaltic pumps. A common solution to address this problem with HPLC systems, is to utilise a vacuum degasser on the inlet side of the pump. A vacuum degasser is fundamentally a chamber kept under vacuum pressure that contains a length of gas-permeable tubing leading the solvent to the pump. Using this technology, any gas dissolved in the solvent will be extracted in the vacuum chamber before it can reach the pump. Vacuum degassers have been shown to be very efficient for removing dissolved gas, they do however fail completely if any undissolved gas bubbles are transported along the tubing.
Published in International LabMate – June 2023
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The Importance of Understanding Pump Flow

Pumps are one of the most common tools enabling liquids to be moved, delivered, pushed through a separation column, supplied as a dose or transferred from one container to another. Several different pumping technologies are available to choose from, depending on your application or problem. As you might expect - a pump designed to pump crude oil through a pipeline has very different requirements compared to a pump designed to deliver a constant stream of medication into a patient’s vein. As such, the term ‘flow’ can be interpreted very differently, depending on the context.
Published in International LabMate – July 2022
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Investigating Variation in Flow from Peristaltic Pumps

Peristaltic pumps find wide application in modern labs, they are considered inexpensive, easy to use and to maintain and, most important of all, are extremely reliable and flexible. The range of application is huge, from simple transfer of a liquid from one container to another in HPLC and Ion chromatographs, to more complex usage as dispensing tools for reagents in flow chemistry.
Published in MicroBioz India – June 2022
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Investigating Variation in Flow from Peristaltic Pumps

With peristaltic pumps, several flow paths can be operated simultaneously. However, many parameters influence the actual flow rate in each channel. Accurate determination of the individual flow rate in the individual channels is crucial for reproducible results.
Published in Lab Worldwide – February 2022
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Specialty Chromatography Detectors: Make or Buy?

Liquid Chromatography of any kind - HPLC, UHPLC, GPC/SEC, Ion Chromatography or FPLC, is based upon the specific characteristics of the utilised separation column to provide a suitable environment for a particular application or investigation. As such, creating an optimised separation is often considered to be the core of an individual liquid chromatography system. Separation alone, however, does not supply answers, it just creates the correct preconditions whereby chromatography detectors are able to reveal the 'secrets' of your sample.
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Common detectors for GPC/SEC Chromatography

This article provides an overview about the detectors most commonly used in GPC/SEC applications, explains differencies within each detector class, provides inforamtions about pro's and con's of each detector and also explores combination of detectors for the most useful hyphenated techniques in GPC/SEC.
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Determination of specific refractive index increment (dn/dc)

The specific refractive index increment (dn/dc) is a fundamental parameter for the determination of molecular weight with Static Light Scattering. Its importance will become clear by observation of the Debye's constant in the SLS equation, where the dn/dc is a squared term. As such, any error in the specific refractive index increment will strongly effect the molecular weight results. This is true for both cases, when SLS is used in batch mode, like in case of a goniometer system, or in flow mode like in case of a MALS Detector in GPC/SEC.
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