چكيده به لاتين
In the first part of this research, a new voltammetric sensor based on carbon paste (CP) electrode modified by a nanocomposite between molecularly imprinted polymer and multiwalled carbon nanotubes (MIP-MWCNT) was prepared for determination of the diazepam (DZ) drug. The obtained results indicated that the electrode modified by MIP-MWCNTs has much higher adsorption ability than the NIP-MWCNTs-CP based sensor. After optimization of the factors affecting the response of the sensor, the calibration curve was drawn under optimal conditions. The obtained calibration curve was shown a linear relationship with DZ concentration in the range of 8.0 × 10−9 to 1.0 × 10−6 M (R2 = 0.9972). The detection limit (LOD) was also obtained 3.77 × 10−9 M. The relative standard deviation (RSD %) for five repeated measurements of 1.0 × 10−7 M DZ was 3.4%. The developed sensor was successfully used for determinations of diazepam in tablet and human blood serum samples.
In the second part of this research, an electrochemical sensor based on graphene-carbon paste electrode (GCPE) modified by MIP nanoparticles (Nano-MIP) was prepared for sensitive and selective determination of chlordiazepoxide drug. The obtained results showed that the GCP electrode modified by MIP nanoparticles (Nano-MIP-GCPE) has much higher adsorption ability to CDP than the NIP nanoparticles modified electrode (Nano-NIP-GCPE). Also, the using of graphene nano sheets in preparation of CPE leads to a significant improvement in the response of electrode to CDP. Under optimized extraction and analysis conditions, the sensor response have a linear relationship with chlordiazepoxide concentration in the range of 6.0 × 10−10 to 7.5 × 10−8 M (R2 = 0.9982) with a detection limit of 2.61 × 10−10 M. The proposed sensor showed good reproducibility for five times measurement of 7.5 × 10−9 M CDP solution (RSD = 3.2%). This sensor was successfully applied for determination of chlordiazepoxide in pharmaceutical formulation and biological fluids samples.
In the third part of this research, the nano-composite between MIP and MWCNT was prepared by suspension polymerization method. In this section, the chlorpromazine drug (CPM) was selected as template molecule.Then, the molecularly imprinted polymer (MIP-MWCNT) and the non-imprinted polymer (NIP-MWCNT) were used as recognition elements for modification of screen printed carbon electrodes (SPCE). After ensuring the appropriate response of prepared sensor to CPM, the factors affecting the performance of the sensor were examined and then the calibration curve was drawn under optimized conditions. The peak current showed a linear relationship with CPM concentration in the range of 7.5 × 10−10 to 2.5 × 10−7 M (R2 = 0.9956) and the detection limit was calculated 2.96 × 10−10 M. Also, the relative standard deviation for investigation of the sensor reproducibility was obtained 4.48% (n=5). Finally, this sensor was used for assay of CPM in tablet and human urine samples.
Keywords: Electrochemical sensor, Molecularly imprinted polymers, Nanoparticles, Diazepam, Chlordiazepoxide, C hlorpromazine
