Ultrasound-assisted emulsification microextraction coupled with high-performance liquid chromatography for the simultaneous determination of fragrance allergens in cosmetics and water.

A simple, inexpensive, and environmentally friendly method based on ultrasound-assisted emulsification microextraction followed by solidification of floating organic drop and high-performance liquid chromatography coupled to diode array detection was developed for the simultaneous determination of 18 potentially allergenic fragrance substances. Several parameters affecting the microextraction process were investigated in detail by the "one-variable-at-a-time" approach. Optimal conditions were the following: 50 μL of 2-dodecanol as extraction solvent, 10 mL of sample containing 150 g/L of salt, and 5 min of sonication at 35°C. Under the optimized conditions, method showed good linearity in the selected ranges, with squared correlation coefficients ranging from 0.948 to 0.999. Limits of detection ranged from 0.001 to 0.154 μg/mL and enrichment factors from 9 to 237. Precision of the method, expressed as relative standard deviation, was checked at two levels obtaining good results (3.3-14.4%). Recovery studies were made in baby bath water and in eau de cologne showing acceptable accuracy. Finally, the developed method was successfully applied to different commercial cosmetic and water samples. The most commonly found analyte was linalool followed by cinnamal and lilial. Most of the analyzed samples contained at least one of the target compounds.