Determination of Pb in lipsticks by flow injection chemical vapor generation isotope dilution inductively coupled plasma mass spectrometry

• Determination of Pb in lipsticks by FI-VG-ICP-MS.
• Validation of methodology by GBW09305 Cosmetic (cream) reference material.
• Lipsticks of different colors are analyzed.
• Isotope dilution, standard addition, and pneumatic nebulization results were compared.
• Screening of lipsticks for Pb.

A flow injection vapor generation method is described for the analysis of lipstick for Pb by isotope dilution inductively coupled plasma mass spectrometry (ICP-MS). A sample homogenate was prepared as emulsion containing 1% m/v lipstick, 0.5% m/v K3Fe(CN)6, 0.5% v/v HNO3 and 0.5% m/v Triton X-100 and was injected into a VG-ICP-MS system followed by sodium borohydride for the vapor generation of Pb. Since the efficiency of hydride generation of Pb in emulsion and that of aqueous solution was quite different, isotope dilution and standard addition methods were used for the determination of Pb in selected lipstick samples. The influences of vapor generation conditions on the Pb ion signal were reported. This method has been validated by the determination of Pb in GBW09305 Cosmetic (cream) reference material. The method was also applied for the determination of Pb in lipsticks of different colors obtained locally. The analytical results obtained by isotope dilution and standard addition methods were in good agreement and also with those of digested samples analyzed by pneumatic nebulization ICP-MS. Under the optimum operating conditions, the detection limit obtained was 0.001 ng mL− 1 in prepared emulsified solutions, corresponding to 0.11 ng g− 1 of Pb in the original lipstick samples.