Colorimetric detection of dichlorvos using polydiacetylene vesicles with acetylcholinesterase and cationic surfactants

Abstract

Widespread use of dichlorvos in agriculture has posed serious concern for food and water contamination. A new colorimetric method for the detection of dichlorvos based on polydiacethylene and acetylcholinesterase inhibition is developed. The blue-to-red color transition of poly(10,12-pentacosadynoic acid) vesicles can be induced by myristoylcholine which is enzymatically hydrolyzed by acetylcholinesterase to myristic acid and choline to prevent the color transition. In the presence of dichlorvos, the hydrolytic activity of the enzyme is inhibited that the blue-to-red color transition is restored with a linear correlation to the dichlorvos concentration. Using UV-vis absorption spectrometer, the limit of dichlorvos detection is 6.7 ppb. A naked eye detection of 50 ppb dichlorvos is achievable by using dimiristoylphosphatidylcholine to the diacetylene mixed lipid vesicles.

Keywords: Acetycholinesterase inhibitor; Colorimetric sensor; Conjugated polymer; Dichlorvos; Organophosphate; Polydiacetylene.