title: Stable isotope dilution analysis of salicylic acid and hydroquinone in human skin samples by gas chromatography with mass spectrometric detection.
abstract: A sensitive and accurate gas chromatographic-mass spectrometric (GC-MS) method has been developed for the quantitative determination of salicylic acid (SA) and hydroquinone (HQ) from human skin samples and cosmetic emulsions. Deuterium labeled SA-d(6) and HQ-d(6) were used as internal standards (IS). The samples were extracted with methanol, dried under nitrogen and derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA)+1% trimethylchlorosilane (TMCS). Quantification was performed in SIM mode with a limit of quantification (LOQ) of 50 ng ml(-1) for SA and 10 ng ml(-1) for HQ. The inter-day variation (R.S.D.) was less than 5% and the accuracy was better than 13.3% for both compounds. The recoveries from the different matrices ranged between 93.1 and 103.3% for SA, and 97.3 and 100.8% for HQ.
authors.affiliation: School of Pharmacy, North-West University, Potchefstroom Campus, Potchefstroom 2520, South Africa.
authors.forename: Anja
authors.initials: A
authors.lastname: Judefeind
authors.forename: Peet Jansen
authors.initials: PJ
authors.lastname: van Rensburg
authors.forename: Stephan
authors.initials: S
authors.lastname: Langelaar
authors.forename: Jeanetta
authors.initials: J
authors.lastname: du Plessis
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D006873:Hydroquinones / Q000032:analysis*; D007554:Isotopes; D012015:Reference Standards; D015203:Reproducibility of Results; D020156:Salicylic Acid / Q000032:analysis*; D012680:Sensitivity and Specificity; D012867:Skin / Q000737:chemistry*
chemical_list: D006873:Hydroquinones; D007554:Isotopes; D020156:Salicylic Acid; C031927:hydroquinone