Determination of total mercury in water and urine by a gold film sensor following Fenton's reagent digestion.

Fenton's reagent (Fe(II) + H2O2) is utilized for the digestion of environmental water samples and urine. Following the digestion, which converts organic forms of Hg to inorganic Hg(II), Hg(0) is liberated by borohydride reduction and measured by a conductometric gold film sensor. Quantitative recovery of Hg from samples spiked with mercuric chloride, methylmercury(II) chloride, and phenylmercury(II) acetate was attainable in the presence of naturally occurring suspended matter and humic and fulvic acids as well as 3% NaCl. The digestion is performed at moderate pH (3-4) and temperature (less than or equal to 50 degrees C) and does not use large amounts of any reagent. Excellent agreement is shown for reference water, wastewater, and urine standards. The limit of detection, facilitated by the low blank value, is 500 pg of Hg or 10 ng/L for a 50-mL sample.