HPLC Determination of Tanning Preventives in Cosmetics

HPLC was applied to the simultaneous determination of 4 tanning preventives,including 2-ethylhexyl-4-dim- ethylaminobenzoate,2-ethylhexyl-4-methoxycinnamate,2-ethylhexyl salicylate and diethylaminohydroxy-benzoyl hexyl benzoate in cosmetics.The sample was ultrasonically extracted with methanol and centrifuged speedily for 10 min.The supernatant obtained was filtrated with 0.45 μm filtering membrane,and then separated on HPLC-Cartridge RP-18e column with methanol-water (88+12) solution as mobile phase.The contents of the 4 tanning preventives were determined at the wavelength 350 nm for diethylaminohydroxy-benzoyl hexyl benzoate and 305 nm for the other 3 tanning preventives.Linear relathionships between the values of peak area and mass concentration were kept in the range within 100.0 mg·L-1,with detection limits (3S/N) in the range of 0.015-0.115 mg·L-1.The values of recovery found by standard addition method were in the range of 92.8%-105.2%,with RSD′s (n=6) ranged from 1.12% to 2.27%.