RISK-BEARING SUBSTANCES IN COSMETICS 173 There were 16 BROWN eye make-up preparations 14 contain iron oxides 2 contain bronze powder 6 contain titanated micas LIPSTICK COLOURS Identification Many excellent papers exist on the paper and thin layer chromatographic identification of lipstick colours. For this reason the choice of methods made for their identification in the 36 samples (18 brands) of lipsticks purchased in February 1972 is only briefly described. A selection of 40 of the most important lipstick colours was made, based on several recent publications in this field. Reference substances were obtained by the kind cooperation of several manufacturers and laboratories. The list of these reference colours is in Table III. There are two important groups of lipstick colours worth consideration from an analytical aspect. Xanthene colours are the principal compounds for indelible types of lipstick. It appears that the industrial reference colours in several in- stances contain minor substances, which are clearly visible on the tlc plates (see Fig. 1). In the actual separation of the sample extracts, this phenomenon might interfere in the identification of a minor spot. A second important group of colours in lipsticks are the lakes of the water soluble dyes. Most of these dyes occur as water-insoluble lakes in lipsticks, because of the undesirability of 'bleeding' on the place of application. Most of the lakes are also practically insoluble in other organic solvents, such as ethanol, chloroform or benzene. Fortunately hot dimethylformamide (DMF) will dissolve many lakes to an appreciable extent thus permitting extraction for tlc analysis. Extraction of lipsticks The Lehmann method (7) was used. It gives five fractions the fat fraction is discarded the main (DMF) fraction and the 'lake' fraction are analysed by tlc and the pigment fraction is analysed by the same chemical methods as used for eye make-up. Mix and heat 100 mg of sample with 10 ml dimethyl- formamide (dmf). Filter. Filtrate =a and residue = b. Defat a by shaking with 2 x 15 ml nHexane. Separate. Hexane-fraction is c and dmf-fraction is d.

174 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS +++ I I I I -I- I I -I- I I • I I • I