Chemistry blasts harmful tanning products for the BBC | Imperial News


Agilent Measurement Suite recently emerged as an expert witness in a BBC investigation.

When BBC News wanted to back a story about dangerous tanning products with science, they turned to Professor Tony Cass, director of the Agilent Measurement Suite. With the high-precision instruments in the suite, he and his colleagues Dr. Trevor Ferris and Dr. Rahma Hassan supporting the BBC’s story with solid data.

The journalists examined tanning products that were heavily promoted by social media influencers and contained the banned artificial hormone Melanotan-2. Inhaled or injected, Melanotan-2 speeds up tanning, but it also has a number of side effects on the body and has been linked to an increased risk of skin cancer.

“The journalists asked if we could analyze some of these tanning preparations and tell them if they contained what they said they contained and if there were other substances present,” recalls Professor Cass. “The tools in the Agilent Measurement Suite are well designed to answer these types of questions.”

The instrument is very sensitive, can detect even very small amounts and is very accurate. Professor Tony Cass Director of the Agilent Measurement Suite

The Agilent Measurement Suite is a 120m2 Facility in Imperial’s Molecular Sciences Research Hub containing advanced chemical analysis instruments generously provided by instrument manufacturer Agilent Technologies or purchased from SynbiCITE, the National Center for Synthetic Biology Translation. The instruments include mass spectrometry, chromatography, spectroscopy and cell analysis systems.

In this case, the answers were provided by liquid chromatography-mass spectrometry (LC-MS), a combination of two different analysis techniques. Chromatography separates any complex mixture of compounds into broad fractions, which are then fed into the mass spectrometer, which measures the charge-to-mass ratio of the substances present.

Measure a ton to the last gram

‘This is very sensitive to be able to detect even very small amounts, and also very accurate to tell you the mass, which is the key parameter in identifying any substance,’ explains Professor Cass. “It’s accurate to about one part in a million, which is like measuring a ton to within a gram. This level of accuracy is a key parameter in identifying the molecule.”

For a substance whose mass is known, like the melanotan in the tanning products, the researchers are looking for a specific peak on the trace coming out of the LC-MS. And just to be on the safe side, they also run a clean, authentic sample through the facility for comparison. This is where the work can get tricky. “In a complex mixture, some of the other components can mask the presence of the substance you’re looking for, so you need to try different separation conditions and develop a method that takes this into account to give you good sensitivity along with accurate mass measurements.”

The BBC journalists also wanted to test claims that the tanning products were 99% pure. A look at the LC-MS trace is enough to dismiss this idea. “You can see over 100 other peaks in the separation, so you can tell there are many other components in the sample,” says Professor Cass. “But it’s another matter to say exactly what those components are.”

Reading from the chemical analysis
LC-MS results from seven samples. The large peak on the left is the melanotan while the other peaks are unidentified impurities and impurities.

Your measurements and what you know of the original mix may give you an idea, but without much further work this remains circumstantial. Ultimately, every proposed substance would have to be compared with an authentic sample. “Given the time and cost constraints, we couldn’t do this for all the other components.”

Chemical fingerprints

However, it would have been interesting to go a little further and use the characteristic LC-MS trace of each tanning product to study its origin. Most hail from China, where the melanotan is likely to be purchased in bulk, then reformulated and bottled for sale. “In principle, one could identify the source based on the signature. So do these different products come from the same lab, or are there different labs scattered across China, each with their own unique fingerprint?”

When we present our instruments with a difficult problem, it challenges us to develop our own expertise and skills. Professor Tony Cass Director of the Agilent Measurement Suite

But the Agilent Measurement Suite had told the BBC team what they wanted to know, and Professor Cass appeared on camera to present the results. “It was a short piece of a short report, but if you have the information and the opportunity, you should share it with the public,” he says. “For us, the project was also an opportunity to test what the instruments can do. When we give them a difficult problem, which was this analytical problem, it challenges us to develop our own expertise and skills.”

“It was an exciting project,” adds Dr. Hasan added. “We expected to find some contamination since the artificial tanning products are unregulated and bought over the internet, but we didn’t expect there to be more than 200+ different connections!”

Consumer protection work was new territory for the suite, the only comparable work being a study of traditional African herbal remedies suspected of being contaminated with medicines. ‘We are open to all types of challenges, be they academic, public or commercial,’ concludes Professor Cass. “We try to be as open as possible so that people can use our skills.”


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