Buying a new piece of laboratory equipment is always a big decision. Many thousands of dollars are often being invested based on relatively little information. We know this can be a difficult decision with a lot riding on it so we’ve put together a list of things to consider when buying an advanced GPC/SEC system. The final decision should depend on your own priorities but this should provide a starting point for the buying process.
Introduction
Buying a new piece of laboratory equipment is always a big decision. Many thousands of dollars are often being invested based on relatively little information. Through self-education on the web, reading marketing materials, discussions with sales and technical representatives, and perhaps a brief demonstration or single sample analysis, you have to convince yourself that a particular solution will work for your situation. We know this can be a difficult decision with a lot riding on it so we’ve put together a list of things to consider when buying an advanced GPC/SEC system. The final decision should depend on your own priorities but this should provide a starting point for the buying process. 1) What’s my return on investment (ROI)? If you are investing heavily in an expensive research tool, you want to know that your investment will come back to you in the long term. This could be higher value, better graded product with fewer quality issues, or it could be a stronger publication record helping to open up future research funds. Coupled in with this question is whether your chosen vendor has a good reputation. You want to be sure that your instrument is supported by a thorough understanding of the underlying principles it uses and you want to know that the vendor can explain those principles to you and that they will support you in your research.2) What’s the real performance? Advanced GPC/SEC systems can be used for a wide array of applications from polymers in plastic containers, to inks, and proteins in biopharmaceuticals. A brochure or a specification sheet can make amazing claims with respect to standard materials under ideal conditions, but how does this relate to your own samples? Does the light scattering detector have the sensitivity you need? Is the viscometer a robust design proven across many applications? Will the results be repeatable and reproducible and can it calculate inter-injection precision? The best conclusions come from the best data and you need to be confident the instrument you buy will give you the best data to put you a step ahead of your competitors. Does the vendor back up their specifications with actual data demonstrating that performance? Ask the vendor to make some measurements of your own samples, either in their applications lab or at an on-site demo. The data generated will be a valuable reference tool when making the final decision and give you an idea of the performance you can expect in your own lab.3) Is this instrument appropriate for my application and will it give me the information I need? The application and desired information should determine the configuration of your advanced GPC/SEC system. Absolute molecular weight is the most common requirement for such a system and this requires light scattering measurements of some kind. Different detector designs (known as RALS, LALS and MALS) can measure the molecular weight of synthetic and natural polymers and proteins. A MALS detector can also be used to measure size and Rg (radius of gyration) for large enough polymers (typically >10 nm radius). When looking to measure structure and branching, this is best done with a viscometer which can make measurements across the entire distribution range. Copolymer or conjugate measurements require two concentration detectors, where refractive index (RI) and ultraviolet (UV) are typical. The separation itself is also extremely important. Some applications require solvents that run better at higher temperatures, for example, DMF or DMSO. In these situations, an integrated, temperature controlled system is critical. This maintains the temperature of columns, detectors and inter-detector tubing. It keeps the entire solvent path heated to reduce back-pressures and prevents repeated heating and cooling which can affect the sample. Make sure your vendor has a good understanding of your application requirements and isn’t trying to force a one-size-fits-all solution or one which may be inappropriate for your application and molecular weight range.>> Download the full Application Note as PDF
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