Simultaneous Determination of Caffeine and Paracetamol Using Activated Glassy Carbon Electrode

Abstract

In this study the electrochemical behaviour of AGCE was compared with bare GCE for the determination of CAF and PA using CV and SWV. The result of CV was shown that, the PA exihibit only oxidation peak current at GCE, which reveals irreversible properties of PA at GCE. Intense oxidation and reduction peak of PA with oxidation peak potential shift to negative potential was observed at AGCE. Even though, its response current was decreased, the oxidation peak potential of CAF was shift to more negative side at AGCE in comparison to GCE. This was due to good catalytic effect of AGCE toward the redox reaction of studied samples. SWV was employed for simultaneous determination of CAF and PA.The relationship between peak current and concentration of PA was studied by varying its concentration from (10 – 180 μM) at constant concentration of 0.5 mM CAF and result in linear over studied range with correlation coefficient of (R2 = 0.990). Similarly, CAF was studied by varying its concentration from (100 – 950 μM) at constant concentration of 10 μM PA and it was also linear with its response over studied range with correlation coefficient of (R2 = 0.991).The detection and quantification limit (LOD and LOQ) were 2.55 μM, 0.36 μM and LOQ 8.49 μM, 1.21 μM for PA and CAF, respectively. The validity of the proposed method was checked by using commercial tablet which contain different amount of CAF and PA and % recoveries were calculated (Recovery = 94.54% and 96.66% for CAF and PA respectively). Uric acid was used as interference to study its effect on simultaneous determination of CAF and PA and the result was shown that uric acid had effect on peak potential and highly minimize the peak current of both CAF and PA.