Electroanalytical determination of sulfasalazine in pharmaceutical and biological samples using molecularly imprinted polymer modified carbon paste electrode

An electrochemical sensor for sulfasalazine determination based on molecularly imprinted polymer (MIP) as recognition element has been developed. A sulfasalazine selective MIP and a non-imprinted polymer (NIP) were synthesized and then incorporated in the carbon paste to prepare the modified carbon paste electrodes. Trace amount of sulfasalazine was determined by using differential pulse voltammetry method based on electrochemical reduction of sulfasalazine at the modified electrodes. The MIP based sensor showed high recognition ability of sulfasalazine in comparison with the NIP based sensor. The influence of experimental parameters affecting sensor response such as carbon paste composition, pH, incubation time, potential scan rate and potential amplitude were optimized. Under optimal conditions, the MIP based sensor exhibited good performance for sulfasalazine over the concentration range of 1.0 × 10−8 to 1.0 × 10−6 mol L−1 with a detection limit of 4.6 × 10−9 mol L−1 and sensitivity 1.11 × 107 μA L mol−1. The MIP based sensor was successfully applied to the determination of sulfasalazine in a commercial pharmaceutical formulation and human serum, offering feasibility and applicability of the sensor to the complex matrices.