DETERMINATION OF MERCURY IN URINE BY FLOW-INJECTION COLD VAPOR ATOMIC-ABSORPTION SPECTROMETRY

A simple, rapid and accurate method was developed for the determination of total mercury in urine samples. The method uses on-line addition of KMnO4 after adding a bromate-bromide reagent to the sample to decompose organic mercury compounds to inorganic mercury(II) ions at room temperature, and determines mercury by flow-injection cold vapour atomic absorption spectrometry. The recoveries of five mercury compounds added to urine were studied; with the proposed method the recoveries of all the mercury compounds used were complete. Good agreement with certificate values of urine reference materials was also obtained. The detection limit of the method based on three standard deviations of the blank was 0.1 mug Hg l-1 in urine with a 500-mul sample loop, achieving a sample throughput of 100 h-1. The calibration graphs were linear up to 30 mug l-1 and with a dynamic range up to 100 mug Hg l-1. At a concentration of 5 mug Hg l-1 in urine, the relative standard deviation was about 2%.