Determination of 10 Kinds of Caine-Type Prohibited Ingredients in Cosmetics by Ultra-Performance Liquid Chromatography-Differential Mobility Spectrometry-Mass Spectrometry

Abstract An analytical method for determination of 10 kinds of caine-type prohibited ingredients in cosmetics was developed. The analytes were enriched through supramolecular solvent-based dispersive liquid-liquid microextraction, followed by instrumental analysis with ultra performance liquid chromatography coupled with differential mobility spectrometry-mass spectrometry. The supramolecular solvent was prepared with dodecanol as extraction solvent and tetrahydrofuran as dispersing agent for vortex-assisted dispersive liquid-liquid microextraction for cosmetic samples. Several factors were optimized including the composition and amount of the supramolecular solvent used in sample preparation and vortex time on the extraction efficiency. The separation of isomers by differential mobility spectrometry was systematically investigated. The results showed that the sample could be effectively extracted by 4 mL of supramolecular solvent consisting of dodecanol and tetrahydrofuran with the help of 3 min vortexing. Under the optimized conditions of carrier gas, separation voltage and compensation voltage, the isomers of benzocaine and tricaine could be well separated by differential mobility spectrometry for qualitative and quantitative analysis, which could hardly be chromatographically separated. The 10 kinds of caine-type compounds exhibited good linearity in their respective concentration ranges, with correlation coefficients better than 0.99. The limits of detection and quantitation were in the range of 0.2–8.0 μg kg −1 and 0.4–20.0 μg kg −1 , respectively. The average recoveries at low, medium and high spiked levels ranged from 70.7% to 94.7% with relative standard deviations from 1.2% to 12.7% ( n = 6). The method is simple, rapid, efficient, and is suitable for the simultaneous determination of the 10 kinds of caine-type prohibited ingredients in cosmetics.