Smartphone-readable Barcode Assay For The Detection And Quantitation Of Pesticide Residues

Organophosphorus pesticide is widely used in pest control such asvegetables and fruits, and is toxic for both vertebrates and invertebrates throughthe inhibition of the acetylcholinesterase enzyme in nerve tissue, leading toaccumulation of the neurotransmitter acetylcholine, which block the nerveconduction, poisoning central nervous system. Enzyme inhibition method ismost commonly used in detection of organophosphorus pesticide residues for itscharacteristics such as simple operation and fast response. This article mainlyintroduced the smartphone-readable barcode assay for the detection andquantitation of pesticide residues.The colorimetric detection principle is based on the irreversible inhibitionof methyl parathion， the yellow intensity of the product is inverselyconcentration dependent. This method presents a smartphone-based analyticalmethod for the rapid detectionof methyl parathion pesticide. Code39was usedin the design of the assay, in particular it is based on the special codingbetween “+” and “-”. The detection solution was injected into the designedPDMS channel plates which forms “the assay lines”; together with the printed background lines they represent the code39“+”, which was read directly witha smartphone. The absence of methyl parathion will result in the barcode “-”,which identifies the test as negative for pesticides. Quantitive detection of thepesticides can be then achieved by colorimetric analysis of the image obtainedwith the smartphone app.The testing results of colorimetric methods mentioned above wasmatched with standard spectroscopic method, proving the feasibility of themethod. Finally the detection of the fruit skin extract pesticide residues provesthat this method is applicable in actual life. The standard product test andsample test was operated at the same time, so as to ensure the activity ofenzyme is consistent, thus improving the accuracy of the experiment. Thesoftware can be free-downloaded from the Internet, and it’s suitable for allsmartphone users, which makes it lowcost and user-friendly control.