Stir bar sorptive-dispersive microextraction mediated by magnetic nanoparticles-metal organic framework composite: Determination of N-nitrosamines in cosmetic products.

A new analytical method based on the recently proposed stir bar sorptive-dispersive microextraction (SBSDME) technique has been developed to determine eight hazardous N-nitrosamines in cosmetic products. As previous step, a simple clean-up is carried out with hexane to remove those highly lipophilic compounds that disturb the SBSDME step. Subsequently, SBSDME is performed by using magnetic nanoparticles-metal organic framework composite, CoFe2O4/MIL-101(Fe), as sorbent to entrap the target analytes, which are later chemically desorbed and measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The experimental variables related to the SBSDME procedure were studied to achieve the highest analytical signal. Under the most favorable conditions, the proposed method was validated providing good linearity; enrichment factors up to 62 depending on the analyte; limits of detection from 3 to 13 µg kg-1; and good repeatability values (RSD < 17.0%). Finally, the method was successfully applied to cosmetic samples composed either of lipophilic or hydrophilic matrices. Quantitative relative recoveries (96-109%) were obtained by using standard addition calibration. The present work expands the applicability of the SBSDME technique, whereas its analytical features make it useful to carry out the quality control of cosmetic samples.