ICP-MS Determination of Trace Amounts of 5 Harmful Metal Elements in Food Nutrition Fortifier

The sample of food nutrition fortifier was dissolved in HNO3 (2+98) solution and the contents of Pb, As, Cd, Hg and Cu in the sample solution were determined by ICP-MS. Yttrium (for det′n. of Cu and As), rhodium (for Pb and Cd) and gold (for Hg) were selected as internal standards to decrease the matrix effects. In analyzing sample of vitamin C for its Hg-content, thiourea should be added as complexing agent to obtain normal recovery. Values of detection limit (3S/N) found were in the range of 0.006-0.064 μg·L-1, and values of RSD′s (n=11) found were in the range of 2.9%-5.9%. The proposed method was applied to the determination of trace amount of the 5 metal elements in 7 samples of nutrition fortifier, and values of recovery found by standard addition method were in the range of 92.0%-105%.