The quantification of total lead in lipstick specimens by total reflection X-ray fluorescence spectrometry

Lipstick is known to contain lead, and this has been a general area of concern. Methods of quantifying lead in lipstick currently require the use of rather harsh digestion procedures given that lipstick specimens are high in their lipid content and contain many refractory materials. A simple method of performing lead analysis in lipstick specimens based on total reflection X-ray fluorescence spectrometry (TXRF) is presented here. Samples were prepared by melting lipstick specimens along with a non-ionic surfactant and an yttrium internal standard followed by homogenization. Solid prepared samples were then finely streaked directly onto a quartz reflector, and TXRF measurements made for 900-s live time. The method was found to produce a mean limit of detection for lead of 0.04μg/g. Precisions were found to be on the order of 11–38% relative standard deviation (RSD) and apparent recoveries for lead between 92% and 106% (n = 8). Although the spreading technique may result in thickness variations that may contribute to the higher than expected variances about the determined lead concentrations, the method presented in this work does show promise as a means of performing routine lead analysis in lipstick specimens without the need for harsh digestion procedures.</p