Objective To develop a method for the determination of diethylene glycol in various cosmetics (emollient water, lotion, cream, gel and paste) with gas chromatography to solve limitations of detection methods used in current practice.
Methods The emollient water samples were extracted with methanol by ultrasonic and detected after filtration; the lotion, cream and gel samples were extracted with methanol with ultrasonic and then centrifuged and filtered; the paste samples were grinded with anhydrous sodium sulfate first, then extracted using ultrasonic with methanol, and finally centrifuged and filtered for detection. The diethylene glycol in the samples was determined with gas chromatography-flame ionization detector (GC-FID) and quantified with matrix-matched external standard method.
Results The calibration curve presented a good linearity in the range of 1 – 1000 μg/mL (r = 0.999 7). Three-level spiked recoveries were carried out using blank cosmetic extractions as substrate; the recoveries ranged from 94.4% to 95.4% for lotion, cream or gel, 85.1% to 96.9% for the paste, and 89.5% to 98.8% for emollient water; while the relative standard deviations (RSDs) were all below 4.86%. The limit of determination was 0.24 μg/mL and the limit of quantitation was 1 μg/mL.
Conclusion The method is simple and easy to operate with less cost, wide linear rang, low detection linearity, and high practical value and it is suitable for the detection of diethylene glycol in different cosmetic matrixes.
DownLoad: