Voltammetric sensor for barbituric acid based on a sol–gel derivated molecularly imprinted polymer brush grafted to graphite electrode

A voltammetric sensor based on a molecularly imprinted polymer (MIP) brush grafted to sol–gel film on graphite electrode is reported for the selective and sensitive analysis of barbituric acid (BA) in aqueous, blood plasma, and urine samples. The modified electrode was preanodised at +1.6 V (vs. saturated calomel electrode), where encapsulated BA involved hydrophobically induced hydrogen bondings, in MIP cavities exposed at the film/solution interface, at pH 7.0. Scanning electron microscopy (SEM) was employed to characterise the surface morphology of the resultant imprinted film of MIP brush. The differential pulse, cathodic stripping voltammetry (DPCSV) technique was employed to investigate the binding performance of the sol–gel-modified imprinted polymer brush, which yielded a linear response in the range of 4.95–100.00 μg mL−1 of BA with a detection limit of 1.6 μg mL−1 (S/N = 3).