Stripping Voltammetric Determination of Analgesics in Their Pharmaceuticals Using Nano-Riboflavin-Modified Glassy Carbon Electrode

Cyclic voltammetric behaviors of three analgesics, acetaminophen (AAP), acetylsalicylic acid (ASA), and dipyrone (DP), were studied using nano-riboflavin-modified glassy carbon electrode. One well-defined oxidation peak each for AAP and ASA and three oxidation peaks for DP were observed. The influence of pH, scan rate, and concentration reveals irreversible diffusion controlled reaction. The SEM analysis confirmed good accumulation of the drugs on the electrode surface. Calibration was made under the maximum peak current conditions. The concentration range studied for the determination of drugs was 0.02 to 0.4 mu gmL(-1) for AAP and ASA and 0.025 to 0.4 mu gmL(-1) for DP. The lower limit of detection observed for AAP, ASA, and DP was 0.016, 0.007 mu gmL(-1), and 0.013 mu gmL(-1), respectively. The suitability of the method for the determination of these analgesics in pharmaceutical preparations and urine samples was also ascertained.