Jan 06 2021 Read 1616 Times The Differential Refractive Index (DRI) detector from Testa Analytical Solution eK offers unmatched accuracy and reliability for determination of absolute concentration and total mass balance in Gel Permeation Chromatography/Size Exclusion Chromatography (GPC/SEC) applications. The baseline signal stability of any liquid chromatography detector is very important, as it is a limiting factor in peak determination. Detector stability gains even more importance where analysis time is long, such as is commonly encountered in high resolution GPC/SEC applications. Use of multiple columns is common in GPC/SEC as a technique to increase resolution and also to increase the available dynamic range in terms of molecular weight. As such, high resolution GPC/SEC measurements can often take 30 to 60 minutes for a single separation. As a result, most HPLC detectors adapted for use in GPC/SEC will show a significant baseline drift between the beginning and end of the chromatogram thus negatively influencing the ability to accurately determine the beginning and end of sample peaks and therefore to calculate the correct polydispersity.