Electrochemsense : Electrochemical Real-Time Pesticide Sensing System
Dhamu, Vikram Narayanan
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Pesticide contamination of produce and water in the United States has been a drastic problem to address partly due to the high overhead costs of screening in produce samples, while the other being the inability to report data in real-time-accurately. In 2007, Glyphosate was the most widely used pesticide in the US agricultural sector. More recently, the use of Glyphosate-based herbicides (GBH) has been reported to have increased more than 100-fold with the emergence of glyphosate resistant weeds. The WHO has classified it as being possibly carcinogenic to humans with more current reports suggesting that a few days of GBH use per year-increases the risk of cancer twofold. In addition to this, it has been known to cause chromosomal damage to cells. But, while there is high interest and a necessity to detect this compound-the challenge however lies in designing a sensitive, low volume sensor that can screen for glyphosate with high specificity directly from produce run-off/extract and report it as useful concentration information. In this study, we have developed a portable real-time electrochemical sensing system that can identify and report trace levels of Glyphosate as below or above the Maximum Residue Limit (MRL) of that particular produce type. Through an optimized label-free assay protocol developed in our laboratory, we have built and characterized an electrochemical sensor device that utilizes Chronoamperometry as the detection modality to characterize concentration of glyphosate pesticide as a measure of current-It gauges the chemical interactions occurring at the active sensing region to modulations in electrical signal response. Using this system makes it possible to detect concentrations as low as 0.01ppm (1ng/mL), which is the sensor’s limit of detection (LOD). The device currently in the form factor of a small box can report contaminant concentration of glyphosate in the produce sample in under a minute (rapid) using a GREEN or RED light for SAFE (low) or UNSAFE (high) threshold ranges based on MRL/residue tolerance values of the produce in question. Hence, we have built an effective, low-cost, portable tool eliminating time consuming laboratory analysis that can be used by consumers and industry alike to keep a check on food safety and quality.