Abstract: The present invention relates to an apparatus and methods for the identification or authentication of liquid products by the addition of an anti-Stokes marker. The invention features an apparatus and method for the identification of a liquid, dynamic or static, that includes adding an anti-Stokes luminescent marker compound to the liquid followed by exposing the compound to a light source of a known wavelength or known wavelengths and then detecting one or more shorter wavelength emissions from the marker, where the identity of the liquid is confirmed by the emission wavelength or wavelengths that are detected and quantified. The irradiating source of light includes, but is not limited to, a laser and other conventional light sources.

Abstract: High pressure liquid chromatography apparatus for use in the analysis of optically-active materials comprises a semiconductor laser diode radiation source 10, a test sample holder 13 through which radiation from the radiation source passes to a detector 16. A polariser 11 and analyser 15 cooperate with a modulator 12 which modulates the rotation of the polarisation of radiation from the laser.