Electrochemical determination of oxazepam drug using molecularly imprinted polymer modified carbon paste electrode

Determination of benzodiazepines in biological fluid is object of great interest for many scientists. Oxazepam is a short-to-intermediate benzodiazepine, which is used for the treatment of anxiety, insomnia and control of symptoms of alcohol withdrawal. In this research an electrochemical sensor based on carbon paste electrode (CPE) modified with molecularly imprinted polymer (MIP) for selective determination of Oxazepam was developed. The MIP particles were synthesized by precipitation polymerization method and characterized by scanning electron microscopy (SEM) and used for modification of CPE. The non-imprinted polymer (NIP) was synthesized using the same process as MIP but without template (Oxazepam). Oxazepam binding results indicated that the sensor modified by MIP had much higher adsorption ability than the NIP based sensor. Some parameters affected on the experimental results such as composition of electrode, extraction and analysis conditions were optimized using experimental design method. Under optimized conditions, Oxazepam peak current showed a linear relationship with its concentration in two linear range of 1.0 × 10-5 - 5.0 × 10-6 M (R2=0.993) and 5.0 × 10-7 -3.5 × 10-8 M (R2=0.994). The relative standard deviation for five measurements of Oxazepam solution by proposed method was obtained 3.35% and the limit of detection (LOD) was 1.45×10-8 M. The developed sensor was successfully used for determination of Oxazepam in tablet and human serum real samples.