Study on dual channel molecularly imprinted sensor for chloramphenicol detection in milk

Taking chloramphenicol（CAP）as template molecule，and o-phenylenediamine（o-PD）as functional monomer，poly（o-phenylenediamine）（PPD）film was electropolymerized on the surface of a glassy carbon electrode（CAP-PPD/GCE）and a dual channel screen-printed carbon electrode（CAP-PPD/SPCE） using cyclic voltammetry（CV），respectively. Furthermore，CAP molecularly imprinted electrode（CAP-MIP/GCE and CAP-MIP/SPCE）was fabricated by eluting the template molecules using the mixed solution of acetic acid and alcohol. CAP was indirectly determined based on potassium ferricyanide as electroactive probe．The properties of molecularly imprinted sensor were investigated. The response current of the two sensor had good linear relationship with the concentration of CAP in the range of 1.0×10-5-1.0×10-4 mol/L and 2.0×10-5-1.4×10-4 mol/L. The detection limit was 5.2×10-6 mol/L and 1.9×10-6 mol/L，respectively. The proposed method was applied to detect CAP in commercial pure milk，and ultraviolet spectrophotometry was used to verify. The results showed that the proposed sensor had the advantages of good selectivity and high accuracy，and was suitable for determination of CAP in milk samples. Compared to CAP-MIP/GCE， the dual channel sensor could achieve two repetitive measurements by using a small amount of sample（50 μL），furthermore，test efficiency and reproducibility were obviously improved