Can Chromatography Detect Adulterated Oil-Based Cosmetics?

Television, newspapers, magazines and social media abound with adverts and advertorials extolling the virtues of various cosmetic brands and products. Cosmetics are big business. Some estimates suggest that by 2020, the worldwide cosmetics and skincare industry will be worth over $650 billion. In the UK, the industry is worth £17 billion and employs close to a million people.

And like many products, where there is a profit to be made, there will be someone looking to take a shortcut to get a bigger profit. Adulteration and fraud afflicts many retail markets, and cosmetics is no different. A recent paper published in the Journal of the Brazilian Chemical Society — Assessment of Adulteration of Cosmetics Based on Vegetable Oils by GC-FID and Lipid Profile Using Direct Infusion Electrospray Ionization Mass Spectrometry (ESI-MS) — has looked at how chromatography can be used to address the problem of adulteration in the cosmetics industry.

Beauty in vegetable oil

Vegetable oils are a common part of our kitchens — used for frying, basting and making salad dressings. But, vegetable oils are also commonly used in cosmetic applications — either on their own or as part of a preparation. The oils are mainly made of triacyl glycerides but contain a complex mix of other components like vitamins, pigments and free fatty acids to give each oils a distinctive signature.

Applying vegetable oil to the skin for cosmetic benefit is nothing new. Applying oil to the skin can protect the skin from excessive water loss by making a protective layer on the skin. It is also thought that applying oil to the skin can help in the regeneration of the skin’s lipid barrier, help in skin metabolization and reduce skin inflammation.

Chromatography measure fake oils

As the team report, there is widespread adulteration of vegetable oils used in cosmetics by cheaper alternatives including soybean oil. The need for quick, safe and simple analytical methods to detect the fake oils is necessary to protect consumers — not just from fake cosmetics, but also from fake oils used in food.

The team behind the paper referenced above, analysed cosmetics with a vegetable oil base (sesame, almond etc) to see if they had been adulterated with lower cost oils. They used gas chromatography with flame ionisation detection along with electrospray ionization mass spectrometry. The use of chromatography and mass spectrometry to analyse complex mixtures is nothing new as discussed in this article, Enhanced Sample Preparation: Precision Peptide Mapping and Quantitation Using UHPLC and Mass Spectrometry.

The team found that using GC-FID and ESI-MS could detect adulteration of vegetable oil cosmetics. Of the samples they tested, several had been adulterated by soybean oil and one contained none of the advertised vegetable oil.

Another day when chromatography is keeping you healthy.