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Abstract

An indirect electrochemical behaviour of total prostatic specific antigen (TPSA) was studied using the differential pulse technique coupled with a three-electrode detection system, which consists of 2mm diameter glassy carbon as working electrode, 2mm diameter platinum wire as an auxiliary electrode and silver/silver chloride saturated potassium chloride as reference electrode (Ag/AgCl sat KCl). The method is based on monitoring the decrease in the zinc acetate reduction peak current, which is due to its interaction with TPSA. Acetate buffer solution (pH4) was used, the potential scanned between   -1.4 V to -0.5V, and the optimum conditions were tested. The calibration curve for TPSA was constructed for a sequence addition of TPSA, and it was linear within the studied concentration range (2.4431- 24.4554) x10-9 M, with a correlation coefficient of 0.9763 and calibration equation y= 0.0308x + 1.287. The binding constant (k) and the thermodynamic parameters (ΔG, ΔH, and ΔS) for Zn2+- TPSA interaction were calculated.