预处理金电极微分脉冲伏安法测定甲醛

Determination of Formaldehyde by Differential Pulse Voltammetry with Pretreated Au Electrode

摘要: 将金电极在0.1 mol·L-1氢氧化钠溶液中,在-0.8~0.8 V电位范围内循环扫描8圈进行预处理。研究了甲醛在预处理金电极上的电化学行为,结果表明:甲醛在该电极上有一对氧化峰,峰电位分别为-0.45 V和0.31 V(vs.SCE)。据此提出了微分脉冲伏安法测定甲醛的方法。在电位-0.56 V处,甲醛的氧化峰点与其浓度在1.0×10-6~1.0×10-3mol·L-1范围内呈线性关系,方法的检出限(3S/N)为8.0×10-7mol·L-1。应用该预处理金电极测定水样中甲醛,加标回收率在95.5%~103.7%之间,相对标准偏差(n=5)在3.9%~4.1%之间。

Abstract: Gold electrode was treated by scanning in the potential range of -0.8 to 0.8 V in 0.1mol·L-1 NaOH solution. The electrochemical behavior of formaldehyde at this pretreated Au electrode was studied. Two oxidation peaks of formaldehyde at the pretreated Au electrode, were observed at the potentials of -0.45 V and 0.31 V (vs.SCE). Based on these findings, a sensitive method for determination of formaldehyde by differential pulse voltammetry was proposed. Linear relationship between values of peak current at -0.56 V and concentration of formaldehyde was obtained in the range of 1.0×10-6-1.0×10-3mol·L-1, with detection limit (3S/N) of 8.0×10-7mol·L-1. The proposed method was applied to the determination of formaldehyde in water samples, giving values of recovery and RSD′s (n=5) in ranges of 95.5%-103.7% and 3.9%-4.1%, respectively.