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 spectrometry. Both the sample and the reagent are sequentially aspirated using a Crison automatic Compact Titrator and impelled into a gas–liquid separation cell. Once there, a N2 flow sweeps the reduced mercury into a measuring cell of an atomic absorption spectrometer. The system proposed allows the detection of mercury in addition to data acquisition and treatment in an automatic way. The linear calibration range ranges between 2 and 50 μg l−1, the 3σb/5 detection limit being 0.34 μg l−1. The relative standard deviation of the method is 0.95% when 0.8 ml of 25 μg l−1 Hg standard solution is aspirated. The sampling rate allowed by this method is 30 injections per hour. The proposed method has been applied to different certified fish and marine sediment samples for which satisfactory results have been obtained.