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With 30 years of chromatography and light scattering experience, the Viscotek GPC/SEC systems and detectors from Malvern provide solutions for all applications of proteins, synthetic and natural polymers.

Molecular weight, Tech Talk, Viscotek »

[12 Aug 2014 | ]

What is multi angle light scattering MALS / MALLS?

Light scattering is the effect of light being re-radiated from a sample containing molecules or particles. This scattering depends on the optical configuration of the setup, and in a typical experimental realization, the light is then detected at one or several different angles.
In the one-scattering-angle solution, the three most  popular designs are 90 degrees (also right angle light scattering or RALS), 7 degrees (also low angle light scattering or LALS), or 173 degrees (also non-invasive back scattering or NIBS). In the multi-angle …

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Malvern Panalytical Events, Mastersizer, MicroCal, Nanosight, Particle size, Viscotek, Zetasizer »

[11 Aug 2014 | ]

Come visit us at the American Chemical Society in San Francisco!
Malvern is exhibiting at the ACS meeting in the Moscone Center South and can be found in the 300 aisle, specifically booth number 326. Due to our ever-expanding range of equipment we have a wider booth than in previous years and you’ll find the following instrumentation on the stand:

Zetasizer  hydrodynamic size and zeta potential from a few microLiters
SECMALS-20 molecular weight detector  compatible  with any chromatography system
NanoSight nanoparticle tracking for high resolution number distributions & concentration info
MS3000 reliable, proven particle …

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Dynamic Light Scattering, Electrophoretic light scattering, Molecular weight, Size Exclusion Chromatography, Tech Talk, Viscotek, Zetasizer »

[15 Jul 2014 | ]

Hyaluronic Acid Analysis
As I am new to blogging I think a brief introduction would be good. My name is John Stenson, I am the Product Technical Specialist looking after the Size Exclusion Chromatography (SEC) related detector systems, known as our Viscotek product line. I am most interested in using our technologies to investigate the properties of Proteins and Biopolymers.
My role is extremely varied with one of the most enjoyable aspects attending conferences,  presenting exciting new research we have carried out and talking with other scientists. As part of this I …

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Gel permeation chromatography, Size Exclusion Chromatography, Tech Talk, Viscotek »

[22 Apr 2014 | ]

Are Lithium Bromide or other salts in your GPC system? Improve the working life of your pump seals by using the seal wash system for mobile phases with salt!
What is one of the best practices to keep any chromatography pump – as for example in the GPCmax or a modular GPC system – in prime operating condition? Connect the back flush and keep the mobile phase fresh.  Over time, leaky pump seals can occur in any chromatography system. This is most commonly associated with DMF (dimethylformamide) containing lithium bromide LiBr …

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Molecular weight, Static Light Scattering, Tech Talk, Viscotek »

[25 Feb 2014 | ]

When light scattering (low-angle LALS, right-angle RALS, or multi-angle MALS) is used for molecular weight detection in chromatography, the eluting mobile phase should be free of any material or particulates other than the sample. Even the best chromatography columns can shed some particulates from their packing material and this shedding often scatters a significant amount of light and can create noise in the light scattering detector signals adversely affecting results.  This noise isn’t present in other detectors because they are not sensitive to particulates in the same way.

To mitigate against …

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Malvern Panalytical Events, Nanosight, Protein Aggregation, Viscotek, Zetasizer »

[28 Jan 2014 | ]

Greetings, Materials Talks readers, from sunny Palm Springs in beautiful Southern California! I wanted to update you on the wonderful conference Malvern has attended here: “Peptalk – The protein science week.”
Peptalk, held each January, is dedicated to the fields of protein and peptide therapeutic development. This year’s event attracted over 1,200 attendees from all over the world. Presentations were divided into seven pipelines covering everything from protein and antibody development, formulation stability, purification and aggregation, all the way to facilities design, manufacturing and packaging.
Malvern was one of 80 suppliers vying …

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Gel permeation chromatography, Tech Talk, Viscotek »

[16 Jan 2014 | ]

PNIPAM is a “smart material” which can form a thermo-responsive hydrogel. With a transition temperature in the 30’s and below body temperature, it has seen significant interest in the field of bioengineering.  Potential applications are artificial muscles, wound dressings, engineered tissues and drug delivery.
This chromatogram shows poly(N-isopropylacrylamide) or PNIPAm. It is a promising copolymer candidate for controlled drug release in polymer-drug conjugates.

Solvent
0.02 M LiBr DMF

Flow Rate [mL/min]
1.00

Column Set
I-MBHMW-3078 + I-MBLMW-3078

Column Temp (°C)
60.0

Injection volume μL
100.0

Concentration [mg/mL]
5.80

Mw Weight Average [Da]
124,361

Sample dn/dc [mL/g]
0.071

Sample IV [dL/g]
0.358

PNIPAM -Poly(N-isopropylacrylamide) is a unique temperature-responsive polymer that …

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Gel permeation chromatography, Tech Talk, Viscotek »

[9 Jan 2014 | ]

Lithium/iodine-PVP batteries were invented over 40 years ago. While the design has improved over the years, the same concept is still in reliable use in implanted pacemakers today. With clinical data covering decades the performance of these batteries is well understood. A critical component of these devices is the reaction of halogens with nitrogen-containing polymers like polyvinylpyridine PVP.

Making the particles stick
A common challenge in both nanotechnology and surface science is the modification of the surface chemistry of a material to allow the addition of specific and relevant functionality. From …

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Gel permeation chromatography, Molecular weight, Tech Talk, Viscotek »

[2 Jan 2014 | ]

When Pete Townshend wrote “I hope I die before I get old” back in 1965’s “My Generation,” the Who guitarist was almost certainly taking an anti-establishment stance rather than fretting about future health issues.
Fortunately for music fans, Mr. Townshend has indeed gotten old.  Luckily for people everywhere, medical technology has also advanced considerably over the past 48 years.
 
Nowadays, many medical procedures exist to help people cope with issues commonly associated with (but not limited to) age-related conditions, such as joint replacement, cataract removal and cosmetic surgeries.  A shared component …

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Gel permeation chromatography, Tech Talk, Viscotek »

[17 Dec 2013 | ]

The Chromatogram Series: Maltodextrin Analysis

Ever wondered why your beer tastes so smooth and creamy? Maltodextrin may be the answer. A commonly used food additive, Maltodextrin is an oligosaccharide of various chain lengths, which improves the mouth feel of beers and similar drinks by modifying the viscoelastic properties of the solution.  An easily digestible oligosaccharide with little to no taste, and moderate sweetness maltodextrin is commonly produced enzymatically from grain products such as wheat or corn.
Here is an example chromatogram of maltodextrin, a poly- or oligosaccharide found on many food …

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Gel permeation chromatography, Tech Talk, Viscotek »

[10 Dec 2013 | ]

December-2013. It is the season to be jolly. Charles Dickens once wrote “we need never be ashamed of our tears” (in his ‘Great Expectations’).  This, of course, presumes that we have sufficient tears in the first place.  For the unfortunate who are afflicted with dry eyes (keratoconjunctivitis sicca), artificial tears have filled the void and provided endless pain relief.  One of the primary components in artificial tears is hydroxypropyl cellulose, a cellulose derivative which acts as a thickener in aqueous solutions and provides ophthalmic protection and lubrication.
Here is an …

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Gel permeation chromatography, Viscotek »

[25 Oct 2013 | ]

Yesterday marked the end of yet another great GPC school in Houston. It was the third one of its kind that we have hosted in our main Viscotek office in 2013, and I hope it was of value to all the attendees.
The mild Texas climate makes our southern office especially popular for these events at this time of the year. And this week was certainly no exception. With our conference room booked almost to capacity, it is great to see that many customers were able to take advantage of …

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Gel permeation chromatography, Tech Talk, Viscotek »

[26 Sep 2013 | ]

Here is an example chromatogram of polystyrene in THF. The run conditions and some results are detailed in the table below.
Wikipedia: Polystyrene is a synthetic aromatic polymer made from the monomer styrene, a liquid petrochemical. Polystyrene can be rigid or foamed. General purpose polystyrene is clear, hard and brittle. It is a very inexpensive resin per unit weight. Uses include protective packaging (such as packing peanuts and CD and DVD cases), containers (such as “clamshells”), lids, bottles, trays, tumblers, and disposable cutlery.

Solvent
THF

Flow Rate [mL/min]
1.000

Column Set
2 x T6000M

Column Temp (°C)
30.0

Injection volume …

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Gel permeation chromatography, Tech Talk, Viscotek »

[17 Sep 2013 | ]

Here is an example chromatogram of polypropylene (or sometimes abbreviated as PP), a member of the polyolefins. The run conditions and some results are detailed in the table below.

Solvent
TCB

Flow Rate [mL/min]
1.000

Column Set
2 x HT CLM6210

Column Temp (°C)
160.0

Injection volume μL
200.0

Concentration [mg/mL]
3.640

Mw Weight Average [Da]
475,242

Sample dn/dc [mL/g]
0.0910

Sample IV [dL/g]
2.1299

 
This sample of moderate molecular weight polypropylene is analysed on the Viscotek HT-GPC system at 160 °C. The chromatogram shows the excellent stability of the system and the low noise level of the light scattering (LALS) even at this high temperature in trichlorobenzene …

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

[13 Sep 2013 | ]

A list of historic Viscotek models
When Viscotek became part of Malvern in 2008 it had already been a market leader in Gel Permeation Chromatography GPC, Flow Injection Polymer Analysis FIPA as well as dilute solution viscometry DSV for over 20 years. Founded in 1984 by Dr. Max Haney who invented the four capillary differential viscometer detector, the company had continuously innovated a portfolio of state-of-the-art instrumentation suitable for addressing unique molecular characterization challenges. Due to their solid build quality we still encounter some of the older generation Viscotek models today – …

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Meet the Experts, Viscotek, Zetasizer »

[29 Aug 2013 | ]

Over 400 delegates from around the world packed into the Durham Centre for Soft Matter last week for the 10th IUPAC International Conference on Advanced Polymers via Macromoleular Engineering.
Durham made an excellent location for such a meeting, the lectures being held in the decidedly 21st century drum-shaped Calman Learning Centre. The poster presentations on the other hand, detailing cutting edge work on drug-delivery, memory-storage and energy-transfer, were held in the 11th century Norman Cathedral. With the conference dinner held in the city’s castle, and the Lindisfarne gospels on display next …

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Size Exclusion Chromatography, Tech Talk, Viscotek »

[29 Aug 2013 | ]

This is a screenshot of the OmniSEC profile of dextran. We offer a set of broad Dextran standards for light scattering and triple detection. The run conditions are detailed in the table below.

Run Buffer
PBS

Flow Rate [mL/min]
0.700

Column Set
2 x A6000M

Column Temp (°C)
35.0

Injection volume μL
100.0

Concentration [mg/mL]
2.97

Mw Weight Average [Da]
73,123

Sample dn/dc [mL/g]
0.137

Sample IV [dL/g]
0.236

Dextran is a typical polysaccharide and chromatographs very well. This dextran has a broad polydispersity index PDI = Mw/Mn value of 1.38.  It is typically used as a system suitability sample for aqueous polymer applications, and often also a good …

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Malvern Panalytical Events, Molecular weight, Viscotek »

[26 Jul 2013 | ]

Yesterday we launched the Viscotek SEC-MALS 20, a new modular multi-angle light scattering detector.  The Viscotek SEC-MALS 20 is an addition to the Viscotek range of GPC/SEC (Gel Permeation Chromatography/Size Exclusion Chromatography) systems and detectors for the measurement of molecular weight and size (Rg) of proteins, as well as natural and synthetic polymers.
We explained how this new MALS detector has new optics designed to maximize measurement quality and certainty and we looked at some of the early applications the system has been used for.
Click here to see the launch presentation of …

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Gel permeation chromatography, Size Exclusion Chromatography, Tech Talk, Viscotek »

[9 Jul 2013 | ]

Here is an extensive collection of Malvern documents for GPC and SEC.
These links to a selection of Application Notes, Technical Notes and Webinars will connect you directly to the corresponding  document or recording on the Malvern website (or the log in prompt which will continue to the document once  you have successfully logged in, registration is free with any email address). Additional information can be found at Malvern’s Resource Center,  however the resource center also encompasses all other Malvern products that might not be immediately relevant to your interest.
The information in this …

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Malvern Panalytical Events, Viscotek, Zetasizer »

[4 Jul 2013 | ]

Malvern exhibited at the Canadian Society for Pharmaceutical Sciences Conference on “Personalized Medicine and Individualized Drug Delivery”

Earlier in June, we exhibited at the “Personalized Medicine and Individualized Drug Delivery” meeting in Vancouver, British Columbia, Canada. The event was jointly organized by the Canadian Society for Pharmaceutical Sciences (CSPS) and the Canadian Chapter – Controlled Release Society (CC-CRS) and took place at the UBC Pharmaceutical Sciences Building, 11-14 June, 2013.
Among the focus topics of this event were biopharmaceuticals, nanomedicines, gene & protein drug delivery. For gene delivery applications zeta potential, size, intrinsic …

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