Indirect determination of propranolol by cathodic adsorptive stripping voltammetry

The beta-adrenoceptor blocking agent propranolol is an electro-inactive compound at mercury electrode; however after reaction with nitric acid it produced the electro-active nitro-propranolol derivative. A highly sensitive adsorptive stripping square-wave voltammetric procedure for the determination of propranolol based on the adsorption of the nitrated derivative onto a mercury electrode was described. The instrumental and solution conditions influencing the adsorption of the drug species at the mercury electrode surface were studied and discussed. After extraction of the drug from the spiked human urine and serum samples, followed, nitration, the present optimized method was applied for the trace determination of the drug in the studied samples. The obtained calibration graphs were linear for 5-200 and 10-150 ng of the drug with detection limits of 2 and 5 ng mL(-1) in human urine and serum, respectively. The mean RSD was 3.8% and 4.6% for human urine and serum, respectively.