As Malvern Panalytical transitions to an OMNISEC-based Gel Permeation Chromatography (GPC) / Size Exclusion Chromatography (SEC) portfolio, I wanted to remind you why the OMNISEC system has quickly established itself as a versatile tool for characterizing and understanding macromolecules (and some not-so-macro-molecules) of many different types. An advanced GPC/SEC instrument harnessing the power of multi-detection, OMNISEC offers an incredible amount of information from a single injection. Available parameters include the following (with more developments on the way):
- Absolute molecular weight and molecular weight moments
- Intrinsic viscosity
- Hydrodynamic radius
- Mark-Houwink parameters and structural information
- Calculated dn/dc value
- Sample concentration and recovery
Key features that allow these molecular parameters to be accessed and contribute to pushing the boundaries of GPC/SEC analyses in a variety of applications are explored in each of the subsequent sections.
The sensitivity of the refractive index (RI) and right angle / low angle light scattering (RALS/LALS) detectors in OMNISEC has been improved over prior generations of instruments. With these enhancements reliable absolute molecular weight data can be obtained for samples at low concentrations, samples with low molecular weight (down to 200 Da!), samples with low dn/dc values, and sometimes a combination thereof.
Low volume considerations
Features such as the low-volume degasser, injection volumes down to 1 µL, and integrated detectors to minimize dead volume help in a variety of ways. The low-volume degasser allows solvent changes to occur more rapidly. Injection volumes as low as 1 µL (with no sample waste) conserve precious sample. And an integrated series of detectors minimizes band-broadening and maximizes each fraction of sample.
The OMNISEC system is great for running all types of samples for absolute MW
Steffany Chou | The Chemours Company
The temperatures of the autosampler (4-60°C), column oven (20-65°C) and detectors (20-65°C) can be individually set per application. The autosampler can be cooled to preserve the stability of biological samples or can be heated to maintain sample solubility. The columns and detectors can be heated to improve baseline stability or decrease mobile phase viscosity.
Compatibility with third-party systems
Flexibility is critical for integration into labs, therefore OMNISEC is available as a complete system or as the detector-only OMNISEC REVEAL unit. OMNISEC REVEAL can connect to pre-existing pump-autosampler units to upgrade the available detectors. And our specialized UPLC REVEAL unit can be connected to UPLC systems to combine the speed and resolution of UPLC with the wealth of information obtained through multi-detection GPC/SEC – get the best of both worlds!
The intuitive OMNISEC software offers a modern workspace designed to maximize the visibility available with current HD monitors to collect and analyze your data. To help you stay current, the latest versions are free and available to download from our website. The software even has a simulation mode you can use for practice and training.
One of the best GPC/SEC instrument/software packages currently available
Todd Pangburn | The Dow Chemical Company
Accessibility and assistance
Availability is an important ability, and with OMNISEC that rings true in multiple ways. First, there are numerous system components that can be easily maintained/replaced by you the user so the instrument is always available for your analyses. These include the viscometer bridge, which can be zeroed and/or replaced as needed, the UV-Vis PDA bulb, the post-column filter, and the delay columns. Second, we, as in Malvern Panalytical, are available to assist via our Helpdesk and with a host of specialized OMNISEC support content such as our GPC/SEC Expert Advice YouTube playlist and an in-depth guide titled The SECret to Success, among others.