Determination of cu (II) in tap water using carbon paste electrode modified with humic acid by differential pulse voltammeter

摘要

Humic acid which is a exchanger and a chatelator metal ions, based on various reports which has done till now, can be used as a modifier of carbon paste electrode. In this work a new carbon paste electrode built by humic acid and it is utilized for determination of copper in tab water. The determination method is differential pluse voltammeter. The rate of modifier in carbon paste was changed in three values( 3%, 4.5% and 6%) the increase of modifier was led to increase of the peaks’ height and potentional of peak was shifted towards more negative potentional. Analytical parameters such as pH of buffer solution, scan rate, effect composition of modified electrode with different contents of CPE, Potential imposed and preconcentration time were studied. In the optimum pH= 4.75, the catalytic reduction peaks current were linearly dependent on the copper concentration. By using differential pulse voltammeter, linear calibration curves were obtained in the ranges of 1×10~(-7) –2×10~(-5) M (D.L = 3.9 × 10~(-8) M) finally, the interference effect of some materials studied and the method was used.