Determination of trace lead in the high salt matrix of comestible CaCO3 by an isotope dilution method with detection by inductively coupled plasma-mass spectrometry

The determination of trace lead in a CaCO3 matrix by isotope dilution coupled anion-exchange and quadrupole-based inductively coupled plasma-mass spectrometry was established. The matrix of CaCO3 seriously affected the determination by clogging the cones of the instrument was removed by the anion-exchange resin column. Effects such as dead time, mass bias, dwell time and the amount of isotopic agent spiked were discussed and corrected. The detection limit estimated by 3× standard deviation of the procedure blank was 2.94 ng g^-1. The results indicated that the lead concentration in all samples tested was far less than 3%, the legislated limit. The recovery mostly ranged from 90 to 110%. The relative standard deviation was found to be <1%.