a new cost-effective method has been developed to trace pesticides in food. Researchers say this enzyme-based technique is quick and cost-effective.

The method uses a specially devised set of screen-printed electrodes, which are coated with enzyme acetycholine esterase (AChE). The enzyme controls nerve impulses and is easily inhibited by pesticides. Thus when the electrodes are dipped in the pesticide-containing sample, pesticides decativate AChE.

This indirectly helps detect the quantity of pesticides since enzyme deactivation is inversely related to the amount of pesticides present in the sample. The greater the amount of pesticide present, the more is the deactivation rate.

"The method can be used to estimate organophosphorous and carbamate-based pesticides in food, drinks and vegetables,' says the lead researcher Priyabrata Sarkar of the University of Kolkata. The device can detect pesticides over the concentration range of 0-10 parts per billion.

Unlike the existing detection practice that takes more time and requires specialised analytical equipment and technical expertise, the new method is rapid and cost-effective. "It takes about 10 to 15 minutes. One set of electrodes cost around Rs 40. We are trying to reduce the cost to around Rs 2 by producing the enzyme synthetically,' says Sarkar. Commenting on the study, Basab Chaudhuri from the Department of Chemical Engineering of the university says, "The method is ideal for Indian conditions.'

The experiment, conducted by researchers from the Department of Polymer Science and Technology of University of Kolkata, Jadavpur University and Cranefield University, the uk, will appear in the forthcoming issue of the journal Ecotoxicology and Environmental Safety.