摘要
提出了草酸的微分脉冲极谱测定方法。草酸在0.05 mol.L-1邻苯二甲酸氢钾-1.0 mol.L-1硫酸锂底液中,扫描范围为-1.80^-1.20 V(vs.Ag/AgCl)时,分别在-1.29 V(Ep1),-1.54 V(Ep2)和-1.76 V(Ep3)电位处出现3个微分脉冲极谱峰,由于Ep3处存在杂质峰干扰,且Ep2与Ep3两峰无法完全分离,试验选择-1.29 V(Ep1)处的微分脉冲极谱峰作为草酸定量分析的测定峰。对乙醛酸共存时乙酸的测定方法经行了论证。草酸浓度与其极谱峰峰电流呈线性关系,线性回归方程y=-24.080 6+37.344 3x,相关系数为0.997 9。方法用于9.018 g.L-1草酸标准溶液的测定,相对标准偏差(n=5)为0.23%,加标回收率在99.6%~100.3%之间。
A differential pulse polarographic method for determination of oxalic acid was proposed. In a base solution of 0.05 mol·L^-1 potassium hydrogen phthalate and 1.0 mol·L^-1 Li2 SO4, and when differential pulse polargoraphic scanning was carried out at the potentials of -- 1.80 V to -- 1. 20 V （vs. Ag/AgC1）, 3 significant polarographic reduction peaks were observed at the potentials of （Ep1） -- 1.29 V, （Ep2） -- 1. 54 V and （Ep3） --1.76 V. To avoid the interference of the reduction product of oxalic aicd, i, e, the glyoxalic acid at Ep3, and the mutual interference at Ep2 and Ep3, the potential of --1.29 V （Ep1） was chosen for the determination of oxalic acid. Linear relationship between values of peak current, and concentration of oxalic acid was shown by the linear regression equation y=-24. 080 6＋37. 344 3 x （r=0. 997 9）. Five portions of standard solutions containing 9. 018 g·L^-1 oxalic acid were determined by the proposed method to test for precision, value of RSD （n=5） found was 0. 23%. Recovery was tested by the standard addition method, giving recovery in the range of 99. 6% -- 100. 3%.
出处
《理化检验（化学分册）》
CAS
CSCD
北大核心
2009年第6期738-739,共2页
Physical Testing and Chemical Analysis(Part B:Chemical Analysis)
基金
国家自然科学基金(20376020)
关键词
草酸
微分脉冲极谱法
测定
Oxalic aeid
Differential pulse polarography
Determination
