KOPTRI provides GPC (Gel Permeation Chromatography) services with an ELSD(Evaporative Light Scattering Detector).

In a typical GPC analysis, we mainly use RI detector and often utilize UV detector for specific cases. However, if the polymer has low RI or UV signals, the measurement becomes very challenging. Especially for siloxane polymers, the RI signal is very weak due to their low dn/dc. Therefore, as an alternative, ELSD (Evaporative light scattering detector) is utilized for measuring these polymers. As shown in ELSD scheme below , the column-separated solution will be sprayed and evaporate in the high temperature to detect through light scattering. Most of the samples are composed of low volatile particles, and the eluent will be completely evaporate during the heating process which will not be detected in the ELSD, and only the sample particles will be detected through the light scattering. Since the eluent is not detected by ELSD, there is no concern for fluctuation of GPC chromatogram baseline, which is very convenient. Also, when it comes to detection, ELSD has much higher sensitivity than RI so that even the molecular weight of very low concentration samples can be measured. RI is dependent on refractive index, which is in function of temperature, and requires hours to stabilize its baseline. On the other hand, ELSD stabilizes much faster, no baseline drifts, no system peaks, and has higher sensitivity. If you need help with analysis, please send us a request by submitting ‘Application Form’ under ‘Contact Us’ tab, and supervising researcher will aid you with a punctual and meticulous reply.