Detecting plasticisers in drinks

A simple red-to-purple colour change test could detect food or drinks contaminated with phthalates, say Chinese scientists. 

Phthalates are used as plasticisers in some types of plastic food packaging; however, due to their toxicity, there are strict rules to prevent them leaching into food or drinks, or being used directly as food additives. In spite of this, there have been several recent scandals where phthalates have entered the food chain. 

The analytical test proposed by Bang-Ce Ye and his team from East China University of Science and Technology, Shanghai, uses gold nanoparticles modified with uridine 5’-triphosphate to detect the phthalates. In the presence of phthalates and Cu²⁺, the modified gold nanoparticles are cross-linked together with the phthalates, forming a bridge between different nanoparticles. The cross-linking reaction causes aggregation of the nanoparticles and the distinctive red-to-purple colour change. 

The team demonstrated that their test was capable of detecting whether drinks such as tea, juices or carbonated drinks had been contaminated with phthalates to a detection limit of 0.5ppm.’The technique is capable of detecting phthalates in concentrations below those set in food safety limits [1.5ppm],’ says Ye. Using a colour change as the indicator means there is no need for expensive and bulky detection equipment so the test could be used to carry out on-site inspections.   

Juewen Liu, an expert in bioinorganic and analytical chemistry at the University of Waterloo, Canada, welcomed the research, saying: ’This is a beautiful example of combining the knowledge of coordination chemistry, supramolecular chemistry and nanoscience to solve an emerging analytical challenge.’

Russell Johnson

Link to journal article

Urine utilisation by microbial fuel cells; energy fuel for the futureIoannis Ieropoulos, John Greenman and Chris Melhuish,?Phys. Chem. Chem. Phys., 2012, 14, 94DOI:10.1039/c1cp23213d