Determination of organic mercury species in soils by high-performance liquid chromatography with ultraviolet...

Reversed-phase high-performance liquid chromatography with ultraviolet detection was optimized for the simultaneous separation and quantification of nine organic mercury compounds: methyl-, ethyl-, phenyl-, methoxyethyl-, ethoxyethyl-, benzoic and tolylmercury, mersalylic acid and nitromersol. The nine compounds were successfully separated on octadecylsilane columns (200 x 3 mm i.d.) by gradient elution with a methanol-water mixture ranging from 30 to 50% v/v. The detection limits for the various compounds are in the range 7.0-95.1 micrograms dm-3. For the extraction of five organomercurials from spiked soils, eight different extraction solutions were tested to differentiate between the total content and the available/soluble fraction of the analytes. Ammonium acetate solutions (1 mol dm-3) and water proved to be suitable agents for the estimation of the available and soluble fractions of methyl-, ethyl-, benzoic, methoxyethyl- and ethoxyethylmercury. For the determination of the total content of methyl- and benzoic mercury in soils, solutions of potassium iodide (1 mol dm-3)-ascorbic acid (0.1 mol dm-3) and oxalic acid (1 mol dm-3) provided recoveries in the ranges 53-81%. None of the solutions tested is suitable for the extraction of ethyl-, methoxyethyl- and ethoxyethylmercury.