Chinese scientists detect melamine in white gold using real gold
Researchers from the Chinese Academy of Sciences and the Engineering Research Center of Food Safety - both in Chongqing, South West China - have devised a "reliable and simple" method to detect melamine using just gold nanoparticles (AuNPs) and a portable UV-vis spectrophotometer.
AuNPs are “easily bonded” with melamine, they wrote in their study, Simple Pretreatment and Portable UV-Vis Spectrum Instrument for the Rapid Detection of Melamine in Milk Products.
In the presence of melamine, the nanoparticles cluster. This causes the AuNP solution to change colour - from wine red to purple.
"This colour change can be quantitatively recorded by a portable UV-Vis spectrophotometer so as to calculate the amount of MEL simultaneously," the study, published in the Journal of Food Quality, continues.
From start to finish, the process takes around 15 minutes and can detect melamine levels as low as 2 parts per million (ppm).
The speed, simplicity and accuracy of the method make it suitable for on-site or field screening of raw milk and milk products, they wrote.
"Therefore, this method is of low cost and is fast, which can satisfy the requirement for on-site rapid monitoring of trace melamine in raw milk products," the study concluded.
Melamine, which contains 66% nitrogen by mass, is an organic chemical widely used in the manufacture of plastics, adhesives, dishware and whiteboards.
Farmers in some countries, including China, have been accused of adding melamine to the milk they produce in a bid to increase its apparent protein content.
While not toxic to adults, melamine can cause kidney stones and kidney damage in infants. In China in 2008, six infants died and 300,000 were sickened after consuming infant formula tainted with melamine.
Source: The Journal of Food Quality DOI: 10.1111/jfq.12146
Title: Simple Pretreatment and Portable UV-Vis Spectrum Instrument for the Rapid Detection of Melamine in Milk Products
Authors: Wanyi Xie, Yu Huang, Wen Yun, Dongyun Tang, Hua Zhang, Chunlei Du, Yonghong Zhu and Wei Zhang