Sequential injection analysis system for total inorganic arsenic determination by hydride generation-atomic fluorescence spectrometry

摘要

A sequential injection analysis systemis proposed for total inorganic arsenic determination by hydride generation-atomic fluorescence spectrometry.The sample,a reducing sodium tetrahydroborate solutioon and a blank solution containing HCl,ascorbic acid and potassium iodide are sequentially aspirated and then dispensed into a gas-liquid separation cell. An Ar flow sweeps the arsine into the flame of an atomic fluorescence spectrmeter.An auxiliary H_2 flow was necessary to support the flame.linear calibration graphs were obtained for arsenic concentrations between 2.5 and 50 #mu#gl~(-1),the detection limit being 0.67#mu#gl~(-1).The relative standard deviation of themethod was 1.8%(n=9)when 0.5ml of a 20 #mu#gl~(-1) As standard solution was aspirated.The sample throughput was 33 samples per hour.The proposed method has been validated by means of reference materials and the results obtained were in good agreement with the certified values.