Researchers at the University of São Paulo (USP) in Brazil have developed a kraft paper-based electrochemical sensor that can detect traces of pesticides in fruit and vegetables in real-time when coupled to an electronic device. In an apple or cabbage, for example, it can detect carbendazim, a fungicide widely used in Brazil despite being banned.
The new device is highly sensitive and resembles the glucometers used by diabetics to measure blood sugar, except that the results of food scanning for pesticides are displayed on a smartphone. "In the tests we performed, its sensitivity was similar to the conventional methods. Plus, it's fast and inexpensive," said José Luiz Bott Neto, a postdoctoral fellow at IFSC-USP.
The device consists basically of a paper substrate modified with carbon ink and submitted to electrochemical treatment in an acid medium to activate carboxyl groups and make detection possible, Bott Neto explained.
In developing the device, the researchers evaluated the stability and structure of the paper substrate.