Biocidal disinfectants are used daily throughout the food chain to limit the development of undesirable microorganisms present in the environment or on surfaces in contact with foodstuffs or animal feed.

The presence of residues of these biocidal products is an issue for human health especially if they are not completely removed during rinsing operations.

Today, we aim to develop innovative electrochemical biosensors as powerful analytical methods to detect these residues of biocides.

Enzyme-based biosensors are known to be more sensitive and selective. So far, only one conductometric sensor is known at present for the detection of surfactants [1]. In this light, we suggested applying the acetylcholinesterase-based voltammetric biosensor for inhibitory analysis of quaternary ammonium compounds (QACs).

In this work, we elaborated an enzymatic sensor based on bionanomaterials film consisting of a fil of carboxylic acid functionalized multi-walled carbon nanotubes (c-MWCNT) modified with the acetylcholinesterase enzyme. In addition to their mechanical stability and good electric conductivity, the c-MWCNT in particular display a large number of binding sites available for enzyme immobilization. These cholinesterase-based sensors are very sensitive and allow for reaching low limits of detection.

Cyclic voltammetry was used to characterize the sensing film deposited onto the surface of electrodes such as glassy carbon and gold electrodes (Au250AT, Au250BT).

The acetylcholinesterase sensors that exhibited good repeatability and stability were applied to the detection of residues of QACs in milk samples.

[1] DOI 10.1088/0957-0233/23/6/065801