Biochemical Detection of Cholinesterase Inhibitors in Water with a New Two-Component Chromogenic Reagent

Abstract

We propose a simple biochemical detector of cholinesterase inhibitors in water that is based on an enzymatic reaction. The detector was designed as a detection tube containing (i) an indication layer with an immobilized butyrylcholinesterase, (ii) a layer with substrate and chromogenic reagent and (iii) an ampoule with buffer. The chromogenic reagent contained a mixture of two triphenylmethane dyes: Guinea Green B and Fuschsin Basic. The absence of inhibitors was indicated by changing the blue color of the indication layer to violet-red. In the presence of inhibitors, the indication layer remained blue-colored. Color change was evaluated visually (by naked eye). The functionality of the detector was verified on aqueous solutions of alkaloid physostigmine and two chemical warfare agents: sarin and VX. The achieved detection limits were 0.01 μg/mL for physostigmine and sarin and 0.005 μg/mL for VX.