Direct determination of inorganic and organic mercury in urine by flameless atomic absorption spectrophotometry using the alkaline-reduction technique--a modification of the method of Littlejohn et al. (1976)

Abstract

A simple and rapid method for determining inorganic and organic mercury in urine was developed by improving the method of flameless atomic absorption spectrophotometry introduced by Littlejohn et al. (1976). In the present method, more than 1ml of 60% KOH solution (final concentration 7.1%; 1.8M) was added to 5ml of urine for atomizing mercury after the addition of stannous chloride as the reductant for inorganic mercury. In the determination of organic mercury reduced by a mixture of stannous chloride and cadmium chloride, more than 11ml of 60% KOH solution (final concentration 34.7%; 8.7M) was needed. In the inorganic mercury determination procedure, the reduction of ethylmercury was not completely inhibited by the addition of acidic L-cysteine solution.The patterns of calibration curves for mercury determination were the same for mercury (II) chloride, methylmercury (II) chloride, ethylmercury (II) chloride and phenylmercury (II) acetate. The detection limit of all types of mercury used was 0.5ppbHg. The recoveries of mercury (II) chloride, methylmercury (II) chloride, ethylmercury (II) chloride and phenylmercury (II) acetate, which were added to urine, were 95.7%, 98.9%, 121.8% and 90.8%, respectively.