Choosing the Right HPLC Detector

Detectors for HPLC determine the identity and concentration of eluting compounds in the mobile phase, and they can be categorized into two types: specific detectors and bulk property detectors. As the name suggests, specific detectors respond to specific compounds and their response is not dependent on the composition of the mobile phase. UV/Vis detectors are the most common examples of specific detectors, as they respond to compounds that absorb UV or visible light at particular wavelengths. Bulk property detectors, by contrast, are the most universal detectors for HPLC. They measure properties common to all analytes by measuring differences in the mobile phase with and without the sample. The universal nature of bulk property detectors places an increased emphasis on the selectivity of the chromatographic column, however they are limited in their sensitivity. The refractive index detector (RI) is the most common example of a bulk property detector.