Photoreduction-hydride generation: a new on-line system for the determination of selenate and selenite

Here we propose the on-line photoreduction of selenate to selenite in coupled systems. Simultaneous determination of both selenate and selenite is achieved by using LC-UV-HG-QCAAS (Liquid Chromatography-UV irradiation-Hydride Generation-Quartz cuvette Atomic Absorption Spectrometry) and LC-UV-HG-ICP/OES (Liquid Chromatography-UV irradiation-Hydride Generation-Inductively Coupled Plasma/Optical Emission Spectrometry). The two methods proposed have the advantages of not requiring the addition of a reducing agent to the eluate and only use 10 min for determination. The detection limits (expressed as μg 1−1 of selenium and calculated as 2σ the background signal) are 6.8 for selenite and 16 for selenate, when using ICP/OES as detector, and 15 for selenite and 33 for selenate when using QCAAS as detector. Precision, expressed as %RSD and calculated at concentrations of about ten times the detection limits, ranges between 4% and 6%.