USE OF AN EVAPORATIVE LIGHT-SCATTERING DETECTOR IN REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OF OLIGOMERIC SURFACTANTS

The sensitivity of the evaporative light scattering detector was found to be dependent on the analyte concentration and the organic modifier concentration: under reversed-phase gradient conditions calibration is necessary for each analyte. Detection limits for alcohol and carboxylic acid homologues were determined. The advantages of helium over carbon dioxide as a nebulization gas for both volatile and non-volatile or thermolabile analytes are a > 30-degrees-C lower operating temperature and a five-fold better signal-to-noise ratio. High-resolution separations of polyether alkyl alcohols were effected by reversed-phase gradient high-performance liquid chromatography with ultraviolet transparent mobile phases. Evaporative light scattering detection was compared with refractive index and ultraviolet absorbance detection at 190 nm and found to be superior in signal-to-noise ratio as well as baseline drift. A column-switching system was designed to allow complete compositional analysis of technical samples of ethoxylated alkyl alcohols and their carboxylic acid derivatives.