AsianScientist (Mar. 5, 2018) – Food scientists from the National University of Singapore (NUS) have developed a rapid and highly sensitive screening technique capable of detecting minute amounts of pesticide residue in vegetables. They published their findings in Food Chemistry.
Synthetic pesticides such as pyrethorids are widely used in vegetable farming to control agricultural pests. While the use of these pesticides improves crop yield, long-term ingestion of excessive pesticide residues through the consumption of fruits and vegetables could lead to adverse health effects.
Several methods, such as column filtration and centrifugation, have since been established to screen vegetable crops for pyrethorid residue. However, they are time consuming and costly, taking up to six hours to process and analyze one sample.
To simplify the procedures, Assistant Professor Yang Hongshun and his PhD student, Ms. Yu Xi, both from the Food Science and Technology Programme at the NUS Faculty of Science, developed polystyrene coated magnetic nanoparticles which can effectively extract pyrethorid residue from vegetable crops for analysis via simple magnetic separation.
The nanoparticles are first added into a liquid sample obtained from vegetables, serving as ‘micro magnets’ to attract pyrethroid molecules. Pyrethroids bound on the nanoparticles are then washed off by a small amount of organic solvent and collected for analysis.
This modified protocol allows analysis to be completed in less than two hours, and is able to detect pyrethroids at a concentration level of as low as 0.02 nanograms per gram of vegetables. The nanoparticles can also be reused up to 30 times, making this screening approach both time and cost efficient.
“Existing screening methods require long processing time and hence it could be challenging to apply such methods to detect pesticide residue in a large batch of samples, which is vital to ensuring food safety. Our method therefore offers a faster and more effective alternative,” said Yang.
Moving forward, the duo intends to expand the applications of their technique to enable screening of different chemical hazards in various food types.
“With small modifications to the extraction process, this method can be used to detect pyrethroids in other food products such as nuts, fruits and vegetable oils. Modifications can also be made to the coating of the nanoparticles to detect other types of pesticides and chemicals including mycotoxins and antibiotics,” said Yu.
The article can be found at: Yu & Yang (2016) Pyrethroid Residue Determination in Organic and Conventional Vegetables Using Liquid-solid Extraction Coupled with Magnetic Solid Phase Extraction Based on Polystyrene-coated Magnetic Nanoparticles.
Source: National University of Singapore; Photo: Pexels.
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