2018 Volume 28 Issue 4 Pages 154-161
Urinary cadmium (Cd) concentration has been used as a biomarker of long-term exposure to this metal in the previous researches. ICP mass spectrometry (ICP-MS) has become a method of choice for measuring urinary Cd concentrations, however, spectral interference from molybdenum oxide (MoO) has to be removed/corrected for accurate analysis. This study evaluated (1) MoO spectral interference in urinary Cd determination by ICP-MS, and (2) the performance of chelate-resin solid phase extraction (SPE) for removal of the interference. Cadmium concentrations in human urine certified reference materials and human urine samples from a male subject were determined by ICP-MS with mathematical MoO interference correction and ICP-MS preceded by SPE, as well as those by electrothermal atomic absorption spectrometry (ETAAS). The sensitivity and accuracy of the determination of urinary Cd was generally satisfactory for all the 3 methods; however, ICP-MS without SPE was found to give a deviated Cd concentrations for urine samples with higher Mo/Cd ratio due to uncertainty in interference correction. It was concluded that ICP-MS with mathematical interference correction is suitable as a routine method for measuring urinary Cd concentrations, but ICP-MS with SPE can be a method of choice for urine with high Mo/Cd ratio and for highly sensitive and accurate urinary Cd analysis.
