12 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS determination of glycerol in a series of glycerine/sarcosinate intermediate solutions. These results have been compared with those obtained by sodium periodate oxidation of the glycerol followed by titration of the liberated formic acid. Table II Glycerol content of glycerine/sarcosinate solutions Method % w/w glycerol ATR 29.8 $0.0 29.9 $0.1 30.0 Oxidation with periodate 29.57 30.12 30.08 30.02 29.93 The ATR method was based on the "absorbance" of the glycerol absorption at 1045 cm -• and the analysis was carried out at an angle of 35 ø . It was found that duplicate determinations agreed to within 0.1ø/0 . I Determination of pyrophosphate and alkyl aryl sulphonate in household cleaner. The ethanol content of after-shave lotions was determined from the "absorbance" of the ethanol absorption at 1045 cm% using an angle of 40 ø. The standard deviation for this anlysis was :• 1.5% at the 50ø//0 w/w ethanol level. This procedure was also used as an alternative method for determining the ethanol content of aqueous distillates obtained from light duty detergent products. The method was superior to that which

IR SPECTROSCOPY TO TOILET ARTICLES AND HOUSEHOLD PRODUCTS involves measurement of specific gravity and comparison with specific gravity tables for aqueous/ethanol systems in that it was quicker, the volume of sample required was much less, and a constant temperature bath at the correct temperature was not needed. o ! ! i 4-000 3ooo 20o0 Determination of moisture in soap. The ATR method for the simultaneous determination of pyrophosphate and alkyl aryl sulphonate, expressed as % w/w NaSO•- grouping, in a household cleaner, the spectrum of which is shown in Fig. 2, was based on the respective absorptions at 1090 and 1180 cm-L The analysis was carried out at an angie of 35 ø and a spot background was taken at 1300 cm -• instead of employing the tangent base4ine procedure. The results for repeat analyses of a sample of this cleaner are recorded in Table III. Table III Repeat determinations of pyrophosphate and alkyl aryl sulphonate in a household cleaner % pyrophosphate 10.0 10.1 10.1 9.9 10.1 10.1 9.8 % NaSOa- 2.15 2.0 2.1 2.1 2.05 2.0 2.15