While talking to customers about their samples, a frequent topic that comes up is whether or not their samples are branched.  Fortunately, I work primarily with Malvern Panalytical’s gel permeation / size exclusion chromatography (GPC/SEC) product range, which in addition to providing molecular weight, intrinsic viscosity (IV), and hydrodynamic radius (Rh) data, offers the ideal technique to observe, and even quantify, the extent of branching within a sample.  In this post, I’m going to describe what it means for a sample to be branched, how branching affects a sample’s molecular …

Determining which gel permeation/size exclusion chromatography (GPC/SEC) system is best for your needs can be a daunting task. Even after you’ve decided to include a light scattering detector to obtain absolute molecular weight data you’re still left to choose between two options: a multi-angle light scattering (MALS) detector or a right angle and low angle light scattering detector (RALS/LALS). Both light scattering configurations will provide the absolute molecular weight of a sample but utilize different approaches toward that common goal. Fortunately, Malvern Panalytical offers both; the modular SEC-MALS 20 unit …

The most common detector in any GPC/SEC instrument is a refractive index (RI) detector.  There are multiple reasons for this, but the most important is because the difference in refractive index between that of a sample solution and that of the same solvent without a sample is directly proportional to the concentration of the sample.  This is why RI detectors are referred to as concentration detectors.  (It should be noted that UV-Vis detectors are also concentration detectors, but require the sample has a chromophore and absorbs light at a detectable …

If you’ve ever analyzed GPC/SEC data collected on your OMNISEC or TDA 305 instrument that included a viscometer detector, you might have observed and wondered about a negative peak that elutes in the viscometer signal long after the sample peak.  This peak is normal and expected, and the following information will hopefully help you understand why it exists.
To start, we need to discuss the basics of the viscometer detector’s design.  The viscometer detector is comprised of four capillaries, a delay column, and two transducers (DP and IP) arranged in the …

To many people, obtaining molecular weight information from GPC/SEC analysis involves a lengthy calibration process.  A series of standards of known molecular weight are analyzed and a calibration curve based on the standards’ retention volume is generated.  This can be a tedious procedure, and the result is only relative molecular weight data.
The inclusion of a light scattering detector in a GPC/SEC system eliminates the need to run a series of standards to generate a calibration curve, as the sample’s molecular weight is measured directly by the light scattering detector.  This …

Ever wondered what it would be like to use Malvern’s OMNISEC GPC system?
Now you can find out, from the comfort of your own desk! Malvern’s OMNISEC Demo at your Desk webinar provides an in-depth look at the OMNISEC hardware and a thorough demonstration of the user-friendly OMNISEC software.
In this webinar, I highlight key features of OMNISEC Resolve, which is the chromatography unit, including the low-volume degasser, low-pulsation pump with back seal washing, autosampler with temperature control from 4-60°C that can make injection volumes down to 5 µL, and a …

Gel Permeation Chromatography school – Become an expert
Have you ever found yourself with a bunch of GPC data, and didn’t know how to use it?  You’re in luck!
Come on down to Malvern’s Houston, Texas facility on October 19-20, 2016 for a two-day course designed to deliver comprehensive knowledge of Malvern’s GPC/SEC technologies and make you an expert!  We will cover the theory behind the advanced detection options of Malvern’s GPC/SEC instruments, as well as providing a thorough presentation of the OmniSEC software.
You’ll leave the course with an understanding of all …

GPC explained in 30 minutes
Macromolecules, including both natural and synthetic polymers and proteins, have become ingrained in our everyday life.
Everything from the plastic in toys, the pipes in your house, to the components in your food and medicine are comprised of macromolecules.  As such, complete and accurate characterization of these materials is critical in order to maintain the integrity and performance of their end products, and also to help develop more novel and functional polymeric components. Gel permeation chromatography, or GPC, is the analytical technique commonly used to provide this essential …

Malvern is offering a two-day course designed to deliver comprehensive knowledge of Malvern’s Viscotek GPC/SEC technologies.
The course will be held in Malvern’s Houston, Texas facility from April 13-14, 2016 and will cover the theory behind the advanced detection options of Malvern’s GPC/SEC instruments, as well as a thorough presentation of the OmniSEC software (version 5.12 and lower). This ensures that users will leave the course with an understanding of all of the hardware and the software that their sample interacts with, and how to extract the most information from their …

Have a question about how to use the new software for Malvern’s OMNISEC GPC/SEC system?  We’ve got you covered!
The new workflow-based design in OMNISEC v10 provides similar capabilities and functionality as Malvern’s previous GPC/SEC software packages, however the modernized arrangement has introduced some differences between the versions.  Whether you’re new to OMNISEC or new to GPC/SEC altogether, we want to make sure that you, as the user, are comfortable with and capable of using the OMNISEC v10 software to get the most out of your data!
In order to ensure this, …

Malvern is offering a two-day course designed to deliver comprehensive knowledge of Malvern’s Viscotek GPC/SEC technologies. The course will be held in Malvern’s Houston, Texas facility from October 21-22, 2015 and will cover the theory behind the advanced detection options of Malvern’s GPC/SEC instruments, as well as a thorough presentation of the OmniSEC software. This ensures that users will leave the course with an understanding of all of the hardware and the software that their sample interacts with, and how to extract the most information from their sample.
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