Determination of formaldehyde by staircase voltammetry based on its electrocatalytic oxidation at a nickel electrode

In this paper, a novel method for detection of formaldehyde (HCHO), based on its electrocatalytic oxidation of HCHO at a nickel electrode, is reported. The mechanism of electrocatalytic oxidation and quantification of HCHO have been investigated by cyclic and staircase voltammetry, respectively. The electrocatalytic oxidation peak potential of HCHO is at about 475 mV vs. Ag/AgCl electrode; the peak current responds proportionally to concentrations of HCHO in alkaline solution. The linear range of detection is from 46.8 to 1640 mu g/L (1.56 x 10(-6) to 5.46 x 10(-5)M) with a correlation coefficient of 0.996 and a detection limit of 23.4 mu g/L (7.80 x 10(-7)M). The relative standard deviation (RSD) is less than 6% (n = 5), and the recovery is in the range 98-106% for real samples. The result is consistent with that from the spectrophotometry.