Electrochemical Detection of Uric Acid Based on a Carbon Paste Electrode Modified with Ta 2 O 5 Recovered from Ore by a Novel Method.

Except for well-known commercial production procedures, this study demonstrates that Ta 2 O 5 particles can be produced. Through a series of steps, highly pure Ta 2 O 5 particles (99.45%) were produced from the raw ore. We have electrochemically detected one of the important nitrogenous compounds present in urine, "uric acid", by a Ta 2 O 5 particle-modified carbon paste electrode (Ta 2 O 5 -MCPE) using cyclic voltammetry. The prepared electrode has shown excellent current sensitivity at a pH of 6.0 phosphate-buffered solution. We have found that 4 mg Ta 2 O 5 -MCPE has recorded the highest current sensitivity of 75.75 μA. The oxidation peak current was varied with the uric acid concentration in the range from 1 to 5 mM at 4 mg Ta 2 O 5 -MCPE. We have calculated the electrode-active surface area for a bare carbon paste electrode and 4 mg Ta 2 O 5 -MCPE using the Randles-Sevcik equation, and the values were found to be 0.0202 and 0.0450 cm 2 , respectively. On the other hand, the calculated values of limit of detection and limit of quantification were reported as 0.5937 × 10 -8 M and 1.9791 × 10 -8 M, respectively, for the prepared 4 mg Ta 2 O 5 -MCPE. The interfere studies revealed that the variation in the electrochemical signal of uric acid in the presence of different metal ions was found to be less than ±5%.