The concentration of Pb in the
injected solutionwas 1.86 ng mL−1. The concentrations of Pb in lipsticks
were quite high; a relatively high q value (0.9) was applied via the
dynamic reaction cell facility. This was done to effectively reduce the
sensitivity of the ICP-MS. Peak areas of the flow injection signals were
used for quantification. Because another isotope of the same element
represents the ideal internal standard for that element, isotope dilution
results are expected to be highly accurate even when the sample contains
high concentrations of concomitant elements and/or losses occur
during sample preparation or during sample introduction into the ICP.
In this work, the concentrations of Pb were determined by isotope dilution
method.