Determination of four nitrosamines in cosmetics using PDMS-coated rotating disk-assisted supercritical fluid...

N-nitrosamines (NAs) are a class of potentially carcinogenic compounds that may pose significant health risks when present in personal care products. Since 1992, the European Union has established legal restrictions to limit the occurrence of NAs in cosmetic formulations. In this study, an innovative extraction method combining polydimethylsiloxane (PDMS)-coated rotating disk sorptive extraction (RDSE) with supercritical fluid extraction (SFE) was developed for the determination of four volatile NAs, N-nitrosodiethanolamine (NDELA), N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), and N-nitrosodipropylamine (NDPA) in complex cosmetic matrices (shampoo, cleansing milk, and body lotion). The extracted analytes were analyzed using high-performance liquid chromatography coupled with UV detection (HPLC/UV). NAs were extracted to 20 mL of water from cosmetic samples (shampoo, cleansing milk and body lotion) with supercritical CO₂ and then preconcentration by Polydimethylsiloxane (PDMS) film on the RDSE. Extraction parameters for RDSE and key factors affecting SFE efficiency were optimized through central composite design methodology. Under these optimized conditions, the SFE-RDSE-HPLC/UV approach achieved limits of detection ranging from 0.24 to 0.36 µg/kg and limits of quantification between 0.81 and 1.17 µg/kg. Average recoveries varied from 84.2 % to 93.0 %, with relative standard deviations (RSDs) falling between 3.8 % and 4.5 %. This SFE-RDSE-HPLC-UV technique demonstrates high accuracy, reliability, and sensitivity, making it suitable for analyzing other cosmetic products vulnerable to N-nitrosamine formation or contamination during manufacturing.