SEQUENTIAL INJECTION-ANALYSIS SYSTEM FOR DETERMINATION OF MERCURY BY COLD-VAPOR ATOMIC-ABSORPTION SPECTROSCOPY

In the present work a sequential injection analysis system is proposed for the determination of mercury by cold vapor atomic absorption spec trometry. Both the sample and the reagent are sequentially aspirated u sing a Crison automatic Compact Titrator and impelled into a gas-liqui d separation cell. Once there, a N-2 flow sweeps the reduced mercury i nto a measuring cell of an atomic absorption spectrometer. The system proposed allows the detection of mercury in addition to data acquisiti on and treatment in an automatic way. The linear calibration range ran ges between 2 and 50 mu g l(-1), the 3 sigma(b)/5 detection limit bein g 0.34 mu g l(-1). The relative standard deviation of the method is 0. 95% when 0.8 ml of 25 mu g l(-1) Hg standard solution is aspirated. Th e sampling rate allowed by this method is 30 injections per hour. The proposed method has been applied to different certified fish and marin e sediment samples for which satisfactory results have been obtained. (C) 1997 Elsevier Science B.V.