In my last post, I highlighted the most common GPC/SEC columns available from the Malvern Panalytical eStore. Just like with columns, scientists rely on the selection of appropriate GPC/SEC standards to generate reliable methods and obtain quality results. In order to accommodate a diverse range of applications, Malvern Panalytical offers a variety of standards. And like columns and other consumables I’ll be discussing in future posts, they can be obtained directly from our eStore!
This post will discuss Malvern Panalytical’s offering of standards for GPC/SEC analyses. Whether you’re using OMNISEC or our SEC-MALS 20 (or both!), the type of standard(s) you’ll need for your application will depend on your mobile phase and column set, as well as which analysis type you’re using. I’ll highlight some of the best sellers, describe when to use them, and include direct links to the corresponding eStore product page. Stay tuned for a future post on popular consumables!
Narrow + Broad
The Narrow + Broad kits are appropriate for light scattering applications and available in multiple variants. Firstly, you use the narrow standard to calibrate the method and detectors. And then second, you use the broad standard to verify the newly created method.
The Narrow + Broad kits include polystyrene, PMMA, PEO/dextran, and pullulan/dextran combinations. The polystyrene and PMMA standards cover the majority of organic applications between them. The PEO/dextran set works for most aqueous applications that use the A-columns. The pullulan/dextran kit is typically used with specific mobile phases, such as 5% acetic acid in water (and cationic columns) and DMSO.
For protein applications, I recommend using bovine serum albumin (BSA). Malvern Panalytical doesn’t sell BSA, but it can be purchased from most chemical suppliers. A neat thing about a BSA calibration is that it serves as the narrow calibration standard (the monomer) and the verification standard (dimer, trimer)!
Low molecular weight standards
If your samples are small you probably use a low molecular weight column set. In that case, the regular Narrow + Broad standards can be too large for your columns! Don’t worry – simply use the low molecular weight polystyrene kit. Created for these exact scenarios, it contains narrow standards with molecular weights of 13 kDa and 6 kDa ideal for low molecular weight columns. Furthermore, these standards are perfect when using an APC-REVEAL system for high-resolution UPLC applications!
Multi-angle light scattering (MALS) detectors work a bit differently than the right angle & low angle light scattering (RALS/LALS) detectors in OMNISEC. Therefore, we offer a special standard kit for aqueous MALS calibrations that includes a narrow PEO standard and a high molecular weight pullulan standard that exhibits angular dependence. This allows you to confirm all angles on the MALS unit are working correctly. For organic applications, the broad polystyrene is sufficiently big enough to observe angular dependence.
Column calibration standards
The standards required for analysis types such as conventional and universal calibration differ from the Narrow + Broad kits discussed above. To perform a column calibration, you’ll need a series of standards to map the separation profile of your column set. For these analyses, we have polystyrene and PMMA kits available for use in organic mobile phases and a PEO kit for aqueous applications. Although they’re not commonly used for protein applications, protein standard kits are available from third party chemical suppliers.
In conclusion, if you are seeking more details please see the Selection Guide for Malvern Panalytical’s GPC/SEC standards. Furthermore, if you have any questions please don’t hesitate to contact us or email me directly at email@example.com.