Voltammetric method optimized by multi-response assays for the simultaneous measurements of uric acid and acetaminophen in urine in the presence of surfactant using MWCNT paste electrode

In the present study, an electroanalytical method for the simultaneous determination of acetaminophen (AC) and uric acid (UA) in urine samples with a carbon nanotube paste electrode (CNTPE) employing a cationic surfactant (cetylpyridinium bromide, CPB) was developed. The optimization of the proposed differential pulse voltammetric method was performed by means of multi-response assays, highly recommended for simultaneous analysis. Under optimized conditions (pH 7.7, phosphate concentration of 0.1 mol L−1, pulse amplitude of 123 mV, modulation time of 5 ms, CPB concentration of 0.30 mmol L−1 and scan rate of 100 mV s−1), a remarkable peak separation of UA and AC at 174 mV was achieved. The linear curves for the simultaneous determination of UA and AC were built in concentration range of 5.0–92.6 μmol L−1 with satisfactory regression of 0.995 for UA and 0.999 for AC. Limits of detection were found to be 0.25 and 0.57 μmol L−1 for UA and AC, respectively, and the precision assessed as relative standard deviation (RSD) for ten determinations was found to be 3.20% and 1.34% for respective concentrations of 10.0 and 72.5 μmol L−1 for UA and 4.3% and 1.6% for AC. The electrochemical sensor with anti-fouling features was successfully applied for the free-interference simultaneous determination of UA and AC in urine samples.