Analysis of Pesticide Content in Selected Onion Samples by Chromatography and Mass Spectrometry

Human health is always promoted by vitamins and minerals derived from vegetables and fruits. However, increased usage of pesticides for high yield poses a significant threat to public health. Pesticides lead to environmental contamination and can also cause various health issues by entering in the human food system.

Pesticides usage has increased in the past several years to improve the agricultural yield and cater the needs of population explosion. This has lead to contamination of vegetables and fruits to a great extent. Pesticides are hence a major threat to both health and environment. The present investigation is focussed on analysis of selected onion samples grown in pune region for pesticide residues.

Samples of fre sh onions (Allium Cepa) were procured by random sampling from various markets in Pune. Onions have a potential threat from pesticides being sprayed. Whole onion samples were crushed, homogenized and pesticides were extracted using suitable solvents. Quantity and nature of pesticides from these homogenized samples were determined using Gas Chromatography-Mass Spectrometry (GC-MS/MS) and Liquid Chromatography-Mass Spectrometry (LC-MS/MS).

Results

Totally 229 pesticides were screened (77 in GC-MS/MS and 152 in LC-MS/MS). A few exceeded the permissible limits (100ppb). GC-MS/MS is used to detect low molecular weight pesticides that are volatile in nature. LC-MS/MS is used to characterize the stable pesticides. About fifty percent of the onion samples consist of pesticide cypermethrin I and three samples consist of pesticides TFNA-AM (Flonic amid). Conclusions: Pesticides present in onions suggest the precautions and care to be taken to protect crops. Knowledge generated from this study will help farming community to judiciously choose and use the pesticides to prevent its entry in to the food chain and thereby promoting public health.