Determination of some insect repellents in cosmetic products by high-performance thin-layer chromatography

A simple and reliable thin-layer chromatographic method for the determinati on of N,N-diethyl-m-toluamide (DEET) and dimethyl phthalate (DMP) in raw ma terial and cosmetic products was developed and validated. A benzene-diethyl ether-cyclohexane (5:3:2, v/v/v) solvent system was used for quantitative evaluation of chromatograms. The chromatographic zones corresponding to the spots of DEET and DMP on the silica gel plates were scanned in the reflect ance/absorbance mode at 230 nm. The method was found to be reproducible and convenient for the quantitative analysis of DEET and DMF in raw material and cosmetic products. (C) 1999 E lsevier Science B.V. All rights reserved.