A sequential injection cold-vapor atomic absorption method for the determination of total mercury

A sequential injection (SI) method for the determination of mercury via col d vapor atomic absorption spectrophotometry is presented. The method differ s from flow injection (FI) cold vapor methods for the determination of merc ury because of the simplicity of the system required for the method: one pu mp, one valve, a gas-liquid separator, and an atomic absorption spectrophot ometer equipped with a quartz cell. Under optimal conditions, the method ha s the following figures of merit: a linear calibration range of 1.0 to 20 m ug L-1; a detection limit of 0.46 mug L-1; and a precision of 0.90% RSD (8 mug L-1). The procedure allows for a sampling rate of one injection per 80 s (excluding sample pretreatment). Results from the determination of mercur y in water and fish specimens are also presented. The figures of merit of t he method are compared to two other SI methods for the determination of mer cury.