离子色谱法测定柠檬酸、柠檬酸钠中的F^-、Cl^-、SO_4^(2-)、C_2O_4^(2-)等

DETERMINATION OF F-,C1-,SO42-,C2O42- IN CITRIC ACID AND SODIUM CITRATE BY ION CHROMATOGRAPHY

利用离子色谱仪,对柠檬酸、柠檬酸钠中的痕量F^-、Cl^-、SO_4^(2-)、C_2O_4^(2-)等进行测定,采用DIONEX ION PAC ASll-HC分离柱,以电导检测器检测,对淋洗分离条件进行了试验。选择NaOH作淋洗液,0.025～0.050mol/L NaOH做梯度淋洗,可使F^-、Cl^-、SO_4^(2-)、C_2O_4^(2-)等很好地分离,其中Cl^-在0.01～200mg/L,F^-在0.05～200mg/L,SO_4^(2-)在0.05～200mg/L,C^2O_4^(2-)在0.1～200mg/L范围内,浓度和响应值有良好的线性关系,检出限分别为F^-0.01mg/L、Cl^-0.01mg/L、SO_4^(2-)0.03mg/L、C_2O_4^(2-)0.03mg/L,回收率为90％～110％。该方法无需前处理,无基体干扰,可用于柠檬酸、柠檬酸钠中F^-、Cl^-、SO_4^(2-)、C_2O_4^(2-)的测定。

The determination of F.,Cl-,SO42-,C2O42-in citric acid and sodium citrate is carried out on Ion Chromatograph with DIONEX ION PAC AS11-HC anion exchange column and electrical conductivity detector.Using a 0.025-0.05 mol/L aqueous sodium hydroxide gradient,F-,C1-,SO42-and C2O42-are well separated.The concentration has a good linear relationship with its response within the scope of F-in 0.05 ~ 200 mg/L,Cl-in 0.01 ~ 200 mg/L,SO42-in 0.05 ~ 200 mg/L and C2O42-in 0.01 ~ 200 mg/L.The limit of detection of each anion is F' in 0.01 mg/L,Cl-in 0.01 mg/L,SO42-in 0.03 mg/L and C2O42-in 0.03 mg/L.The recovery is 90% ~ 110%.No pretreatment is required and no matrix interference exists in this method.