Preparation of new generation electrochemical sensors and their use in electroanalytical analysis of some cephalosporin group antibiotics

Electrochemical analysis of cephalosporin group antibiotics cefotaxime, ceftazidime and ceftriaxone was performed using a glassy carbon electrode modified with poly(bromocresol purple). For this, first of all, the most suitable electrode modification was determined by optimizing the experimental conditions for the electrochemical polymerization of bromocresol purple on the glassy carbon electrode surface. Then, qualitative and quantitative analysis of cefotaxime, ceftazidime and ceftriaxone was performed in the direction of oxidation using cyclic voltammetry, differential pulse voltammetry and square wave voltammetry methods. It was determined that the redox reactions of cefotaxime, ceftazidime and ceftriaxone were irreversible in the analyzes performed in different buffer media by cyclic voltammetry. Scan rate studies performed by cyclic voltammetry showed that the redox reactions of these drug active substances were diffusion-controlled. Differential pulse voltammetry and square wave voltammetry methods were used for the quantitative analysis of the drug active substances. The linearity ranges of the obtained calibration graphs were 8.0×10-9 – 8.0×10-6 M (correlation coefficient 0.998) for cefotaxime by differential pulse and square wave voltammetry with the detection limits of 1.18×10-9 and 1.46×10-9 M, respectively; for ceftazidime, 1.0×10-8 – 6.0×10-6 M (correlation coefficient 0.999) by differential pulse voltammetry and 8.0×10-9 – 8.0×10-6 M (correlation coefficient 0.998) by square wave voltammetry with the detection limits of 2.03×10-9 and 1.77×10-9 M, respectively; for ceftriaxone, 8.0×10-9 – 8.0×10-6 M (correlation coefficients 0.998 and 0.999) by differential pulse and square wave voltammetry with the detection limits of 1.52×10-9 and 1.51×10-9 M, respectively. The precision of the methods used was examined by repeatability studies. Finally, quantitative analysis of the drug active substances from pharmaceutical dosage forms and human serum was performed without any purification. As a result, an efficient and economical modified electrode with high sensitivity and selectivity was obtained for the electrochemical analysis of these drug active substances.