Detection of harmful chemicals in plastic toys

Detection of harmful chemicals in plastic toys
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A method for quickly identifying prohibited additives in plastics

Ma, X. et al.: “Fast screening of prohibited chemicals in plastic toys using ambient ionization mass spectrometry,” International Journal of Mass Spectrometry (2019)

Children often put toys in their mouths, so the plastics used to make their toys must be free from harmful chemicals. However, some plastics contain additives that make them unsafe. Now, research published in the International Journal of Mass Spectrometry outlines a method for quickly and accurately detecting unwanted additives in children's toys.

"Our method enables on-site detection of harmful plastic additives in under three minutes. It can be used for routine screening of plastics and help ensure all plastic toys are safe for children," says Xiaoxiao Ma from Tsinghua University in China.

Plastic additives are used to improve a plastic's properties or appearance. Dangerous additives may be added intentionally or permitted additives incorporated into the plastic incorrectly can also pose a risk. Checking the safety of plastics is important but, until now, methods were slow and involved many experimental processes. On-site screening of plastic products was not feasible.

Now, the China-based team have developed a rapid, sensitive and simple method to detect prohibited additives in plastics and plastic toys. Instead of crushing the plastic to get at its bulk, they sample and analyse the plastic's surface. This is easy and saves time.

Using the technique, the analysis of a plastic item can now be achieved in under three minutes. With such fast processing times, the technique has great potential for high-throughput screening of toys and other plastic products.

Initially, plastic from the surface is extracted using organic solvents. Then, samples are analysed via two ambient ionization mass spectrometry methods: zero-voltage paper spray ionization and transmission low-temperature plasma probe. In their initial experiments, the team have detected a broad range of prohibited substances in plastics, including some plasticizers, disperse dyestuffs, and aromatic amines.

"Screening plastics for prohibited additives is very important – especially if they are used to make children’s toys," says Ma. "Children are at great risk if a toy contains harmful additives as they are in close contact with their toys and often put them in their mouths."

Ma and his team hope that their technique can be adapted and developed for routine plastics screening. When used with a miniature mass spectrometer, on-site screening at customs can be done quickly and easily. This will ensure the future safety of plastic toys and other plastic products worldwide.