Electrochemical Sensor for Trichloroacetic Acid with Chitosan/Ionic Liquid/Myoglobin Composite Film Modified Carbon Ionic Liquid Electrode

In this paper direct electrochemistry of myoglobin (Mb) in a chitosan (CTS) and ionic liquid (IL) composite film was achieved with a carbon ionic liquid electrode (CILE) as the working electrode Ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM]EtOSO3) was used as not only the binder for CILE but also the modifier in the composite film. UV-Vis and FT-IR spectroscopic results indicated that Mb retained its native structure in the composite film. A pair of well-defined quasi-reversible redox peaks of Mb was obtained on the cyclic voltammogram in pH 7 0 phosphate buffer solution (PBS) with the formal potential (E-0') at -0 216 V (vs. SCE), which indicated that the fabricated composite film provided a suitable microenviroment for the promotion of the direct electron transfer rate between Mb and the underlying electrode. Based on the cyclic voltammetric data, the electrochemical parameters of Mb in the modified electrode were calculated. The Mb modified electrode showed an excellent electrocatalytic activity towards the reduction of trichloroacetic acid (TCA) with the linear concentration range between 0.8 similar to 16 0 mmol/L and the detection limit as 0.3 mmol/L (3 alpha) Based on the CTS-IL-Mb/CILE a new third generation biosensor was constructed.