High-performance liquid chromatographic determination of six p-hydroxybenzoic acid esters in cosmetics using Sep-Pak florisil cartridges for sample pre-treatment.
A rapid and simple method is described for the simultaneous determination of methyl, ethyl, isopropyl, n-propyl, isobutyl and n-butyl p-hydroxybenzoic acid esters (parabens) in cosmetics by high-performance liquid chromatography (HPLC). The method involves a single extraction of parabens with diethyl ether and clean-up on a Sep-Pak Florisil cartridge. Fat-soluble excipients in the diethyl ether extracts are removed through the cartridges with hexane-chloroform (75:25). Parabens are then eluted from the cartridges with hexane-ethyl acetate (70:30) and determined by HPLC on a reversed-phase column with water-methanol (50:50) as the mobile phase using sec.-butylpraben as an internal standard. The method was applied to samples with complicated matrices such as cream, milk lotion, lotion and cleansing foam, and the recoveries were 99.0-102.3% with coefficients of variation of 0.3-1.2%.
Maeda
Y
Y
Shizuoka Prefectural Institute of Public Health and Environmental Science, Japan.
Yamamoto
M
M
Owada
K
K
Sato
S
S
Masui
T
T
Nakazawa
H
H
Fujita
M
M
D002851:Chromatography, High Pressure Liquid; D003358:Cosmetics / Q000032:analysis*; D062385:Hydroxybenzoates / Q000032:analysis*; D007202:Indicators and Reagents; D010226:Parabens / Q000032:analysis*
D003358:Cosmetics; D062385:Hydroxybenzoates; D007202:Indicators and Reagents; D010226:Parabens