Indirect Estimation of Free Prostatic Specific Antigen (FPSA) on Glassy Carbon Electrode Through its Interaction with Manganese Acetate Using Differential Pulse Voltammetric Technique.

Indirect electrochemical properties characteristics of free prostate-specific antigen (FPSA) were investigated using the differential pulse voltammetric (DPV) technique, employing a three-electrode system. This setup included a 2 mm diameter glassy carbon electrode as the working electrode, a 2 mm diameter platinum wire serving as the auxiliary electrode, and a silver/silver chloride saturated potassium chloride electrode as the reference electrode. (Ag/AgCl sat KCl). The method is based on observing the decrease in the manganese acetate reduction peak current which is due to its interaction with FPSA. Acetate buffer solution (pH4) was used, the potential scanned between -1.0 V to 0.5V and the optimum conditions were tested. A calibration curve for free prostate-specific antigen (FPSA) was established based on a series of sequential additions of the analyte. The response to FPSA additions was linear within the studied concentration range (5.4980 - 13.6633) x10-7 M, with a correlation coefficient of 0.9581 and calibration equation y = 0.0073x + 0.6451. The binding constant (k), as well as the values of ΔG, ΔH, and ΔS were calculated to assess the thermodynamic characteristics of the Mn+2- FPSA binding.