Voltammetric sensor based on a composite of chitosan, graphitized carbon black and polyarylenephthalide with molecular imprints for the determination of clarithromycin

For selective determination of the antibiotic clarithromycin, a voltammetric sensor based on a glass-carbon electrode modified with a composite of chitosan, Carboblack C graphitized carbon black and polyarylenephthalide containing diphenylene-thio- and diphenylene oxide fragments in the main chain of the polymer in the ratio of 1 : 2 with molecular imprints of clarithromycin obtained by phase inversion method was developed. The composition and morphology of the modifying coating were studied using IR spectroscopy and scanning electron microscopy. The electrochemical and analytical characteristics of the sensor were studied by electrochemical impedance spectroscopy, cyclic and differential-pulse voltammetry. Optimal conditions for analytical signal registration were selected. Using [Fe(CN) ]63−/4− as a probe, the linear range of determined concentrations was 1 × 10-7 -5 × 10-4 M with a detection limit of 5.3 × 10-8 M. It is shown that the use of a polymer with molecular imprints of clarithromycin increases the sensitivity of the sensor almost 10 times compared to the non-imprinted polymer. The proposed sensor was tested on samples of urine, blood plasma, as well as food products (meat, milk), the degree of extraction was 90-96, 80 and 92%, respectively, and the relative standard deviation did not exceed 10% in all cases.