Single-drop microextraction followed by in-syringe derivatization and GC-MS detection for the determination of parabens in water and cosmetic products

A single-drop microextraction (SDME) method followed by in-syringe derivatization and GC-MS determination has been developed for analysis of five parabens, including methyl, ethyl, isopropyl, n-propyl and n-butyl paraben in water samples and cosmetic products. N,O-Bis(trimethylsilyl)acetamide (BSA) was used as derivatization reagent. Derivatization reaction was performed inside the syringe barrel using 0.4 mu L of BSA. Parameters that affect the derivatization yield such as temperature and time of the reaction were studied. In addition, experimental SDME parameters such as selection of organic solvent, addition of salt, extraction time and extraction temperature were investigated and optimized. The RSD of the method for aqueous samples varied from 8.1 to 13%. The LODs ranged from 0.001 (n-butyl paraben) to 0.015 (methyl paraben) mu g/L, and the enrichment factors were between 23 and 150.