Researchers in Belgium have road-tested a technology that could be used to screen cosmetic products for illegal whitening agents.
The team from the Scientific Institute of Public Health used a technology called attenuated total reflectance infrared spectroscopy (ATR-IR) alongside simple chemometric analysis to identify samples of creams, lotions and soaps containing illegal substances.
They recorded spectra for 150 suspicious cosmetic products and compared them to test samples representing both bona fide agents - with approved whitening agents such as kojic acid, arbutin and nicotinamide - as well as illegal agents that were adulterated with corticosteroids, hydroquinone and the severe acne drug tretinoin.
The latter agents were banned them from the European cosmetic market via an EU directive that came into effect in 2010, but demand for whitening agents means that unscrupulous groups are still distributing them in the EU market.
The ATR-IR approach was able to discriminate between legitimate and illegal samples with a high degree of accuracy and low rate of false positives, according to the scientists. Moreover, the testing can be carried out using a simple, small instrument that requires no sample preparation and so may be suitable for use by customs officers.
Illegal whitening agents are often encountered in the European market and can represent "a considerable risk to public health, since they are often characterised by severe side effects when used chronically," say the researchers.
The research is published in the Journal of Pharmaceutical and Biomedical Analysis.