Miniature Photometers for Liquid Chromatography

Abstract A series of miniature photometers has been developed for use as on-stream detectors in systems for liquid chromatography. All of the detectors feature dual-beam, dual-wavelength operation without mechanical or electrical switching of either wavelength or signal. The two types of detectors originally developed—ultraviolet (254 and 280 nm) and colorimetric (any two choices of visible wavelengths)—have been integrated into a single modular instrument that can be converted from ultraviolet to use with visible wavelengths by substituting source and filter modules. Both straight-through vertical quartz tube flow cells of 3-mm i.d. and Z-cell modules with 10-mm light pathlengths are available. A single-unit power-source and rangeswitching box is used with any configuration of the detector.