Simultaneous determination of 11 preservatives in cosmetics and pharmaceuticals by matrix solid-phase dispersion coupled with gas chromatography

Abstract

A convenient method was developed for simultaneous determination of 11 preservatives in cosmetics and pharmaceuticals. Matrix solid-phase dispersion had been optimized as the sample pretreatment technology, using Florisil as a dispersant, anhydrous sodium sulfate as a dehydrant, formic acid as an additive, and n-hexane and ethyl acetate as eluents successively, and followed by gas chromatography–flame ionization detection on a TR-5 capillary column. Experimental results showed that 11 preservatives were baseline separated within 22 min. Good linearities were observed in the concentration range of 0.53–250 μg/mL for all analytes, and there were also minor differences. All correlation coefficients (r) were more than 0.995. The average recoveries at 3 levels of spiked samples ranged from 80% to 124% with 0.9–12% intra-day RSD and 1.8–12% inter-day RSD. The limits of detection were less than 0.18 μg/mL for all analytes. Besides, there was no obvious matrix effect on the analytes. The conclusion was that the developed method was simple, cheap, accurate, precise, and environment-friendly, in addition to existing little matrix effects. It could be recommended to determine 11 preservatives individually or in any their combinations to not only in liquid and gel cosmetics but also in liquid medicine and ointment.