Application of butyrylcholinesterase-based biosensor for simultaneous determination of different toxicants using inhibition and reactivation steps

Abstract

Fast and simple detection of toxic compounds in aqueous solutions is important for agriculture and pollution monitoring. Enzyme-based electrochemical biosensors are a promising platform for this task, but they usually lack the ability to distinguish between toxicants if more than one toxicant is present in the sample. Herein, we propose a new method of detection of various toxic compounds in complex multi-component water samples using an electrochemical biosensor and additional stages of enzyme reactivation. The biosensor is based on butyrylcholinesterase immobilized on the surface of conductometric transducers using glutaraldehyde cross-linking. It was shown that the biosensor is sensitive to organophosphorus pesticides, heavy metals ions, glycoalkaloids, but has a limited sensitivity to mycotoxins and surfactants. We propose a procedure for the analysis of complex samples with several reactivation stages to be able to determine which category of toxicants is present. Glycoalkaloids are reversible inhibitors and biosensor's activity is restored by washing in working buffer; heavy metal ions and pesticides are irreversible inhibitors and biosensor's activity is restored by incubation in EDTA and PAM-2 solutions, correspondingly. This biosensor can be used for the detection of separate toxicants or for analysis of their mixtures in aqueous samples. It can be also used for the evaluation of total toxicity of the samples and applied for water quality monitoring.