Gel permeation chromatography (GPC is a type of chromatography that uses size to separate analytes within a solution. This differs from other types of separation techniques which may utilize either the chemical or physical interactions of the analytes to separate them. GPC is regularly employed to determine the molecular weight, and distribution of said weight, of samples such as polymers. GPC detectors are used to continuously monitor the weight of the polymer. Currently, the most sensitive detectors are UV photometers while the most common one is a differential refractometer (DRI). However, multi-detectors capable of combining different detector types into one system.