Acetylcholinesterase biosensor for inhibitor measurements based on glassy carbon electrode modified with carbon black and pillar[5]arene

Abstract

New acetylcholinesterase (AChE) biosensor based on unsubstituted pillar[5]arene (P[5]A) as electron mediator was developed and successfully used for highly sensitive detection of organophosphate and carbamate pesticides. The AChE from electric eel was immobilized by carbodiimide binding on carbon black (CB) placed on glassy carbon electrode. The working potential of 200mV was obtained in chronoamperometric mode with the measurement time of 180s providing best inter-biosensors precision of the results. The AChE biosensor developed made it possible to detect 1×10−11–1×10−6M of malaoxon, 1×10−8–7×10−6M of methyl-paraoxon, 1×10−10–2×10−6M of carbofuran and 7×10−9–1×10−5M of aldicarb with 10min incubation. The limits of detection were 4×10−12, 5×10−9, 2×10−11 and 6×10−10M, respectively. The AChE biosensor was tested in the analysis of pesticide residuals in spiked samples of peanut and beetroot. The protecting effect of P[5]A derivative bearing quaternary ammonia groups on malaoxon inhibition was shown.