4 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS quacy of this scheme is its inability to isolate or identify the powerful dye solvent when present. Selection of a method of analysis required an evaluation of the relative merits of the techniques of selective solubility, chromatography, and instru- ment analysis employing x-ray, ultraviolet, or infrared rays. My selection was narrowed down to selective solubility and chromatography in order that the apparatus used would be available in even the most modestly equipped laboratory. Furthermore, as Wilks (5) observed, in his recent article en- titled "Infrared Analysis for Cosmetics," that technique has serious limita- tions. Its limitations most pertinent to this subject were: (1) that the com- posite spectrum of a mixture of a dozen or more components may be too complicated to break down into the respective spectra of the individual Sample Trichlorethylene (T C E) T C E Soluble Total T C E Soluble (Total Base q- Dye) Evaporate off solvent T C E Soluble Acetone Soluble T C E Insoluble TCE T C E Insoluble Acetone Acetone Insoluble GROUP I Lake Pigmerit Water Soluble GROUP II THF Alcohol THF Acetate Propylene Glycol Polyols Water Insoluble Minus T C E I Residue Extract with acetone, chill, filter Cold Acetone Soluble ! Minus Acetone Residue I Petroleum Ether Naphtha Soluble Naphtha Insoluble GROUP V Hydrophobic Oils GROUP IV Hydrophilic Oils (castor oil) Cold Acetone Insoluble GROUP III Lanolin Waxes Hydrocarbons Solid Liquid Figure 2.

SEMIQUANTITATIVE ANALYSIS OF LIPSTICK 5 components and (2) that the analyst is handicapped by the inadequate library of infrared curves of materials related to cosmetics. The other analytical instruments have comparable drawbacks. The method to be described utilizes differential solubility to effect frac- rionation into major groups (marked with Roman numerals) with subse- quent chromatographic separation of the components within a particular group. Figure 2 represents a diagrammatic scheme of the proposed analysis. Naturally the lakes and pigments are insoluble in all organic solvents. All other components of the mass are soluble in trichlorethylene. The exact amount of lake plus pigment is ascertained by treating a weighed sample of lipstick with trichlorethylene, filtering and extracting the residue in a Soxhlet apparatus with trichlorethylene and acetone respectively, to remove any adhering base and dye. The trichlorethylene-acetone insoluble material represents the lake plus pigment (Group I). The trichlorethylene soluble fraction is then extracted with water. The commonly cited powerful dye solvents which are water soluble thus become separated into the aqueous layer, Group II, Figure 3. Group II Water-Soluble Fraction (tetrahydrofurfuryl alcohol, tetrahydrofurfuryl acetate,* propylene glycol, and polyol containing fraction) I Decolorize with charcoal Aliquot A Aliquot B Aliquot C Aliquot D Test for Periodate Barium Use either to detect presence presence test for silico- of tetrahydrofurfuryl acetate of primary propylene tungstate by means of a positive saponi- alcohols glycol test for fication number polyols • •- or '•""• Use for the quantitative de- termination of the polyols by means of the precipitate it forms with barium silico- • • tungstate THFA quan. Azeotropic distil- by vacuum lation for quantL distillation tatire determina- tion of propylene glycol * Tetrahydrofurfuryl acetate quantitatively by calculation from saponification number after it has been positively identified. Figure 3 The trichlorethylene soluble-water insoluble material is heated to evap- orate off the solvent. The residue is then extracted with cold acetone. The dye and oils of the ester variety go into acetone solution while waxes, lanolin, and the parafl:inic hydrocarbons. remain insoluble. This latter insoluble fraction has been designated Group 1II, Figure 4. The, acetone-