Determination of dopamine in blood serum and urine samples by differential pulse voltammetry at an iodine-coated platinum electrode

While platinum electrode shows hyperactivity towards adsorption and surface processes, iodine-coated platinum electrode offers remarkable inertness toward them. Therefore, iodine-coated platinum electrodes lend themselves to probe chemical species in the bulk solution without intervention from adsorption and surface processes. The current work presents utilization of iodine-coated polycrystalline platinum electrode as a voltammetric sensor for determination of dopamine in serum and urine samples. Differential pulse voltammetry (DPV) at iodine coated polycrystalline platinum electrode is the technique of choice whenever higher sensitivity is sought. DPV with a scan rate of 5 mV/s was applied for determination of dopamine in PBS at pH 7. The anodic peak related to dopamine oxidation in the above-mentioned solution was centered at ~0.1V vs. Ag/AgCl quasi reference electrode. The linear range for the developed method was between 1.0 and 100 µM. The anodic peak current showed excellent linearity with dopamine concentration (R2 =0.9977) over the above-mentioned range. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.29 µM and 0.96 µM respectively which attests to the high sensitivity of the developed method. The proposed method was successfully applied to the analysis of dopamine in serum and urine samples. The percent recovery values ranged from 94.4 to 104.5% attesting to the accuracy of the developed method and absence of determinate errors.