Determination of mercury in urine by ICP-MS with direct dilution

Objective To modify the method of inductively coupled plasma mass spectrometry (ICP-MS) for the determination of mercury in urine.

Methods Urine samples were directed diluted with 200 μg/L Au⁺-5% HNO₃ solution, and the mercury content in urine was analyzed by ICP-MS using bismuth (²⁰⁹Bi) as an internal standard and Au⁺ solution to eliminate the mercury memory effect.

Results Mercury concentration had a linear correlation coefficient r of 0.9994 within the range of 0.00-2.00 μg/L, and the minimum detectable concentration was 0.012 μg/L. The high, medium and low mass concentrations of mercury had an average spiked recovery of 105.8%, 102.0% and 100.3%, respectively. The relative standard deviation (RSD) of intra-day precision was below 5.97%, and the RSD of inter-day precision was 1.55%-4.84%. Common interfering elements did not interfere with the determination, and urine samples remained stable for 3 days at room temperature and under refrigerated, frozen, and cryogenic conditions.

Conclusion The modified method is rapid and accurate with good sensitivity and repeatability, and it is suitable for the determination of mercury in urine.