A new differential pulse voltammetric method for the determination of nitrate at a copper plated glassy carbon electrode

A differential pulse voltammetric method for the determination of nitrate has been described, which is applicable to the analysis of natural water samples with nitrate levels greater than 2.8 x 10(-6) M. A reduction peak for the nitrate ions at a freshly copper plated glassy carbon electrode was observed at about -0.50 V vs Ag \AgCl\ KClsatd electrode in a solution of 2.0 x 10(-2) M Cu2+. 0.5 M H2SO4 and 1.0 x 10(-3) M KCl and exploited for analytical purposes. The working linear range was established by regression analysis and found to extend from 2.8 x 10(-6) M to 8.0 x 10(-5) M. The proposed method was applied for the determination of nitrate in natural waters. The detection limit of the method was 2.8 x 10(-6) M and the sensitivity was 0.9683 A . L/mol. The possible interferences by some ions such as phosphate, nitrite and some halides were determined and found to lead to shifts of the peak position and increasing the peak heights.