The Studies on Analytical Test Methods for Cosmetics. II. : Microdetermination of Lead in the Presence of Bismuth in Lipsticks by Dithizone Extraction Method

It was possible to determine lead in the presence of bismuth in lipsticks by dithizonate colorimetry after complete removal of bismuth by treatment with ion-exchange resin. Separated of bismuth and lead was examined by their determination by atomic absorption spectrophotometry. The test method used was as follows : a sample (1g) of a lipstick containing bismuth was ashed and the residue was extracted with 30 ml of dil hydrochloric acid. The extract was passed through a column (diam. 1.2cm) filled with strong base anion-exchange resin (AG 1-X8, 100-200 mesh, Cl- form, 8g) and lead was eluted with 70ml of 8N hydrochloric acid. The effluent was concentrated and lead was determined by the ordinary dithizone method. The analytical results from model lipstick (20% BiOCl) containing about 40 ppm of lead showed little variation and good reproducibility. The coefficient of variation was 3.3%. The lead content of commercial lipstick containing various quantities of BiOCl was less than 5 ppm in each by this method.