Detection of whitening agents in illegal cosmetics using attenuated total reflectance-infrared spectroscopy

• ATR-IR spectra were recorded for 150 suspicious cosmetic products.
• ATR-IR spectra were related to illegal whitening agents present using chemometrics.
• a k-NN model was able to discriminate between samples containing illegal substances and samples containing none.
• Illegal samples could be attributed to the illegal component present.

Cosmetic products containing illegal whitening agents are still found on the European market. They represent a considerable risk to public health, since they are often characterised by severe side effects when used chronically. The detection of such products at customs is not always simple, due to misleading packaging and the existence of products containing only legal components. Therefore there is a need for easy to use equipment and techniques to perform an initial screening of samples.The use of attenuated total reflectance-infrared (ATR-IR) spectroscopy, combined with chemometrics, was evaluated for that purpose. It was found that the combination of ATR-IR with the simple chemometric technique k-nearest neighbours gave good results. A model was obtained in which a minimum of illegal samples was categorised as legal. The correctly classified illegal samples could be attributed to the illegal components present.

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