Application of Doehlert matrix to the study of flow injection procedure for selenium (IV) determination

A method for the rapid determination of selenium is reported. It is based on the injection of selenium sample into a stream of KI and subsequent measurement of the increase of the absorption at 290 nm due to the formation of I3−. A Doehlert matrix was applied for the determination of the optimal working conditions. With the developed method, a linear calibration curve from 1 to 10 ppm was obtained. For the analysis of semiconducting thin layers of CuInSe2 (CIS), a cationic resin was added to the sample solution in order to eliminate the effect of copper and indium on the absorbance values. With the developed procedure a sample throughput of 36 samples per hour and a relative standard deviation 1.1% was achieved.