Quantification of sunscreen benzophenone-4 in hair shampoos by hydrophilic interactions thin-layer chromatography/densitometry or derivative UV spectrophotometry

Benzophenone-4 (bz4) was separated from surfactants,dyes,preservatives,and other components of hair shampoos by thin-layer chromatography on silica gel 60 stationary phase,with ethyl acetate-ethanol-water-ph 6 phosphate buffer (15: 7: 5: 1 v/v/v/v) as mobile phase. densitometry scanning of chromatograms was performed at 285 nm. the densitometric calibration curve for bz4 was nonlinear (second-degree polynomial),with r>0.999. the limits of detection and quantification were ca. 0.03 and ca. 0.1 μg spot-1,respectively. the results obtained by hptlc-densitometry were compared to those obtained by zero and 2nd derivative uv spectrophotometry. in the case of spectrophotometric methods,calibration curves were linear with r>0.9998. the chromatographic method was fully validated. © 2015 anna w. sobańska et al.