A simple and rapid capillary gas chromatography (GC) method is described for the quantitative determination of 2,6-di-tert-butyl-4-"methylphenol (BHT) antioxidant in soap bars, fatty acids, and related intermediates. The procedure involves blending the sample with dimethylformamide in the presence of 2,4-di-tert-butylphenol (DTBP) internal standard, filtering the mixture, silylating an aliquot with BSTFA (bis-trimethylsilyltrifluoroacetamide) and quantifying by capillary GC using flame ionization detection. The silyl derivatization and nonpolar capillary column (12 m, methyl silicone, fused silica) provided resolution of BHT from certain fragrance component interferences. The method has a detection limit of approximately 10 ppm. Soaps fortified with BHT showed recoveries of 97.1 -+ 3.7% at the 200 ppm level and 92.3 -+ 2.2% when spiked at the 75 ppm level. The effect of bar soap storage time on BHT content is also demonstrated.

A high pressure liquid chromatography method is described for the identification and quantitation of aminocarboxylate chelating agents in bar soaps. The method involves reacting the sample with cupric sulfate which precipitates the soap and forms a water soluble aminocarboxylate‐copper complex. The complex is identified and quantified versus suitable standards by HPLC using an anion exchange column with dilute sulfuric acid mobile phase and UV measurement at 254 nm. The method is specific and sensitive with a detection limit of approximately 0.005%. Average recoveries of about 85% were obtained for soap samples spiked with individual chelating agents in the range of 0.01% to 0.10%.