Apparatus for the detection of analytes in a fluid, for example the eluant from a liquid chromatography is described. Solvent is evaporated from the eluant to produce a stream of particles when analyte is present in the fluid. The resultant stream of particles is passed through one or more beams of radiation, typically visible light, and radiation scattered by the particles is detected at least at a first angle to a beam of radiation and at a second, different, angle to a radiation beam to produce a signal indicative of the presence of the analyte.Chromatographic apparatus incorporating the detector and methods of operating the detector and chromatographic apparatus are also described.