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Molecular weight

Absolute molecular weight determination and measurement of molecular weight distribution.

Gel permeation chromatography, Molecular weight, OMNISEC, Size Exclusion Chromatography, Tech Talk »

[23 Feb 2017 | ]

Recently, I’ve presented a new webinar focusing on the protein characterization using the OMNISEC, the highest quality Gel Permeation Chromatography (GPC) / Size Exclusion Chromatography (SEC) system for the measurement of absolute molecular weight, molecular size, intrinsic viscosity, branching and other parameters. Thank you to all participants for your interest and attention during the webinar.
In this webinar, I highlighted the key features and benefits of the OMNISEC system. How to run samples and analyze data and how to access repeatability of multiple sample measurements.

As usual, after the live section of …

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Meet the Experts, Molecular weight, OMNISEC, Particle size, Tech Talk, Zeta potential, Zetasizer »

[30 Jan 2017 | ]

Malvern Instruments takes part at the 8th International Symposium on the Separation and Characterization of Natural and Synthetic Macromolecules (SCM-8) at Rhone Events & Congrescenter. The main interest of the conference is the separation and characterization of large molecules. The target audience includes specialists from analytical chemistry, polymer science, and life-science communities.
Malvern is a sponsor of the conference so keep an eye out for us at our booth. In addition, I will give a talk on Thursday February, 2nd about ‘Combining Multi-Detector GPC Measurements with Ultra-High Performance GPC Separations’. The …

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Gel permeation chromatography, Malvern Events, Molecular size, Molecular weight, OMNISEC, Size Exclusion Chromatography, Viscotek »

[8 Dec 2016 | ]

Version Française
The French symposium of the French Group of Studies and Applications of Polymers (GFP) is the major French congress of polymers.
The 45th edition took place recently in Marseille under the bold architecture of the Villa Méditerranée, designed by Stefano Boeri, a committed actor of the Italian political and cultural scene.

During this conference, we presented the benefits of Viscotek SEC MALS 20.
The SEC-MALS 20 multi-angle light scattering detector  can be used on all GPC / SEC systems and especially Malvern’s latest OMNISEC range. The 20 signals of the SEC-MALS detectors connected …

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Français, Gel permeation chromatography, Malvern Events, Molecular size, Molecular weight, OMNISEC, Size Exclusion Chromatography, Viscotek »

[8 Dec 2016 | ]

English version
Le colloque national du Groupe Français d’études et d’applications des Polymères (GFP) est le congrès français majeur des polymères.
La 45ème édition s’est déroulée récemment à Marseille sous l’architecture audacieuse de la Villa Méditerranée, conçue par Stefano Boeri, acteur engagé de la scène politique et culturelle italienne.

Durant ce congrès, nous avons présenté les avantages du Viscotek SEC MALS 20.
Le détecteur de diffusion de lumière multi-angle Viscotek SEC-MALS 20 peut être utilisé sur tous les systèmes de GPC/SEC et notamment sur le dernier OMNISEC de la gamme Malvern. Les signaux des 20 détecteurs du SEC-MALS …

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Customer experience, Dynamic Light Scattering, Electrophoretic light scattering, Molecular size, Molecular weight, Particle size, Zeta potential, Zetasizer »

[20 Oct 2016 | ]

How can I save paper and print a Zetasizer report as a PDF?
Why print?
The Zetasizer software includes several popular report options. The most frequently used of these is probably the Intensity PSD (M), which gives a compact overview of the results. It lists the z-average and up to three peaks by intensity with their respective mean size, the area under the peak in % intensity and the standard deviation of the peak. In addition, several relevant sample identifiers and measurement conditions, like the sample name,  file name, refractive index of …

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Gel permeation chromatography, Malvern Events, Meet the Experts, Molecular weight, OMNISEC, Size Exclusion Chromatography, Tech Talk, Viscotek »

[13 Sep 2016 | ]

Together with Sysmex, our distributor in Benelux, we are proud to be Gold Sponsors of the International Symposium on GPC/SEC and Related Techniques, taking place from 26-29th September in Amsterdam.
One of our technical experts, John Stenson, is looking forward to presenting some exciting new data in his talk “Combining multi-detector GPC measurements with ultra-high pressure GPC separations” at 3:30 pm on Wednesday 28th September, and says:
“This presentation will discuss the issues related to dispersion and how these can be minimized. We will then show the first high quality data from a combined multi-detector/ UPLC™ …

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Label-free analysis, Malvern Events, Molecular weight, Spraytec »

[21 Apr 2016 | ]

“I’m looking to study the aggregation kinetics of my nanoparticles using the Zetasizer Nano ZS.
Is there a way to make time-resolved size measurements using this instrument?”
The Zetasizer has become a fairly standard sizing tool for nanoparticles, as the size and the size distribution of particles and molecules in solution can be assessed within minutes using Dynamic Light Scattering (DLS). If samples are not stable, results will not be consistent or repeatable (which would be flagged by the trend analysis within the Expert Advice tab); however, DLS can then be used to provide insight into …

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Dynamic Light Scattering, Molecular size, Molecular weight, Protein Aggregation, Tech Talk, Zetasizer »

[21 Jan 2016 | ]

How do I know the minimum concentration needed for measuring the size of my protein?

We are asked this question all the time when we are demonstrating the Zetasizer.  Happily, if the Zetasizer software is installed (and it can be downloaded for free, by the way) there is a minimum concentration calculator integrated – so it’s simple! The calculator can be accessed from Tools – Calculators – Concentration Utilities – Minimum Concentration Calculator
Let’s look at a few examples to get an idea of some typical values for your samples. The left …

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Archimedes - Particle Metrology System, Insitec, Kinexus, Meet the Experts, Molecular structure, Molecular weight, Particle size, Rheometry - Rotational »

[12 Oct 2015 | ]

Last week my kids got very frustrated with warm French toast and a new brand of chocolate spread. The French toast, was …of course…warm, and the chocolate was misbehaving: melting and dripping on their fingers …
Now, French toast (and chocolate spread) is a staple at our house but somehow this never happened before. Mom learned the lesson fast: for this new chocolate spread let the French toast cool first! But the little neurons started firing (wonder… I know, but it happens sometimes)…
Little questions and answers in my head: why now? – …

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Molecular weight, Nanosight »

[18 Aug 2015 | ]

Higher Order Structure Consortium for biopharmaceutical proteins

Case studies on technical decision making with biophysical data
During the development of proteins for use as biopharmaceuticals, the primary structure (amino acid sequence) is important in defining protein activity.
Due to the complex nature of protein drugs, compared to small molecule drugs, biophysical techniques are important tools in the characterization of the protein’s higher-order structure (HOS) to understand the protein’s stability, folding, structure, and functional activity. HOS is characterized variety of biophysical methods including:

Mass spectrometry (MS)
Circular dichroism (CD)
Fourier transform infrared spectroscopy (FTIR)
Raman spectroscopy
X-ray crystallography
Nuclear magnetic …

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Molecular weight, Size Exclusion Chromatography, Static Light Scattering, Viscotek »

[6 Aug 2015 | ]

Looking over an old powerpoint file from Viscotek, an interesting slide on a unique application stood out. Investigating samples of the 20S Proteasome by light scattering in conjunction with refractive index RI was able to clearly determine whether a particular sample contained ‘filled or empty’ proteasomes.
In that case, both the empty and the loaded proteasome showed an RI peak at the same elution volume. Thus with conventional calibration, one would have had to conclude that these samples had the same molecular weight. However light scattering revealed that the filled proteasome …

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Gel permeation chromatography, Molecular size, Molecular structure, Molecular weight, OMNISEC, Size Exclusion Chromatography, Tech Talk »

[14 Jul 2015 | ]

Multi-detector SEC – 10 reasons why protein scientists need one
In a previous post I listed the top ten reasons why a polymer characterization scientist might want to upgrade to multi-detector Gel Permeation Chromatography/Size Exclusion Chromatography, but there are similar points to be made as to why a protein characterization scientist might do the same.  We often focus on the benefits of our own systems but sometimes we may miss the benefits of the basic technique.
If you are a protein characterization scientist and you find yourself thinking, “My UV detector works …

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Molecular size, Molecular structure, Molecular weight, Particle shape, Protein Mobility, Zetasizer »

[30 Jun 2015 | ]

The Zetasizer has some optional advanced protein features that you may not be aware of:
DLS Debye Plot: a dynamic Debye plot of the measured hydrodynamic size as a function of sample concentration to obtain the dynamic Virial coefficient (also known as kd, or interparticle interaction parameter)
Mixture Viscosity: estimates the viscosity of a mixture of dispersants of known viscosity, using the assumption that the total viscosity is a volume fraction weighted sum of the component viscosities. The mean viscosity is based on the volume fraction and the individual viscosities of the component …

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Molecular structure, Molecular weight, OMNISEC, Viscotek »

[23 Jun 2015 | ]

Gel Permeation Chromatography (GPC) is a very popular analytical tool for characterizing natural and synthetic polymers.  This Wednesday Dr. Wei Sen Wong will show results from Triple Detection GPC systems for various polyacrylonitrile (PAN) samples in a webinar presentation.  Molecular weight (MW) distribution and structural information (Mark-Houwink plots) are of special interest to PAN research as well as for product and process specifications (QC).  His presentation shows GPC data that differentiated PAN samples with copolymer and/or branching features.  In addition, flow injection polymer analysis (FIPA) can be a fast and reliable tool for …

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Gel permeation chromatography, Molecular size, Molecular structure, Molecular weight, OMNISEC, Tech Talk »

[19 Jun 2015 | ]

When we are talking to customers about advanced Gel Permeation Chromatography (GPC) systems, we can explain why ours are the best on the market or how their excellent sensitivities means you can measure polymers with lower molecular weight than ever before.  We could tell you how the latest system, OMNISEC, reduces servicing time and costs with its new design of viscometer. Sometimes though we come across the question of why someone would want to invest in a multi-detector advanced GPC system.
Maybe you are thinking, “I’ve got a conventional system with …

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Dynamic Light Scattering, Meet the Experts, Molecular weight, Particle size, Static Light Scattering, Zetasizer »

[11 Jun 2015 | ]

In dynamic light scattering (DLS) we are usually mostly concerned with the level of intensity fluctuations – nevertheless we do need to see a good signal before we can analyze it. The signal strength is the scattering intensity and it is measured in photons per second, or most often as in the Zetasizer in kilo counts per second, kcps for short. The actual average number of photons per second arriving at the detector is also called the mean count rate, the actual count rate, or just the scattering intensity.
What is the mean count rate?
If the detector …

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Molecular structure, Molecular weight, Protein Aggregation »

[21 May 2015 | ]

We recently published a new application note on protein characterization using our latest SEC system, OMNISEC, and I wanted to bring your attention to this elegant piece of work that beautifully shows the kind of information you can get from a multi-detector system and, perhaps more importantly, the kind of information you might be missing from a single-detector, UV-based system.The chromatogram below shows a typical chromatogram of a standard protein,    β-amylase:

It looks pretty typical with a monomer and a small amount of aggregates, right? Wrong!
Let’s looks again with a multi-detector …

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Gel permeation chromatography, Molecular weight, OMNISEC, Size Exclusion Chromatography, Tech Talk »

[25 Mar 2015 | ]

A couple of weeks ago I had the opportunity to present a live webinar through Chemical & Engineering News about how our latest solution for Gel Permeation Chromatography/Size Exclusion Chromatography (GPC/SEC), OMNISEC, can help our customers with their synthetic polymer applications.
OMNISEC is a complete system for GPC/SEC measurements including a pump/degasser/autosampler module in OMNISEC RESOLVE and an advanced multi-detector module including RI, UV/Vis, Light scattering and IV detectors in OMNISEC REVEAL.
During the webinar we covered measurements from simple polymers like polystyrene to fascinating drug delivery polymers such as PLGA. At …

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Gel permeation chromatography, Molecular weight, Size Exclusion Chromatography, Static Light Scattering, Viscotek »

[10 Mar 2015 | ]

How to get the latest OmniSEC GPC software
One of the new developments at the Malvern exhibit at Pittcon is the OMNISEC system. If you are in New Orleans, come by our booth 3545 and take a look. We have already talked with quite a few existing users of our TDA and 270 systems. Did you know that the latest sofware version for our GPC / SEC systems is available for download from our website?
Where can I find and download the latest version of the OnniSEC software?
How to update your OmniSEC software:
Quick answer: OmniSEC software version 5.10
Did …

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Gel permeation chromatography, Malvern Events, Molecular structure, Molecular weight, OMNISEC, Size Exclusion Chromatography, Tech Talk »

[10 Mar 2015 | ]

I’m currently at Pittcon, the annual laboratory science conference and expo.  This year it’s in New Orleans, not too far from our factory in Houston.  Since New Orleans is known for its Cajun food and the Food Labs conference is going on at the same time, it made me think of the ways OMNISEC, our latest Gel Permeation Chromatography/Size Exclusion Chromatography (GPC/SEC) system can be used to support work in the food industry.
I’m sure you know that there are plenty of polysaccharides in processed foods but did you know how …

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