硝酸银比浊法测定硫酸氧钒中氯离子

Determination of chloride ion in vanadyl sulfate by silver nitrate turbidimetry

采用氢氧化钠-过氧化氢处理硫酸氧钒样品,冰乙酸调整试样溶液酸度后沸水浴加热沉淀分离钒,用硝酸银比浊法测定了滤液中氯离子的含量。讨论了硝酸用量、硝酸银加入量、测量时间等对溶液浊度的影响,确定了最佳测定条件。结果表明,将硝酸银溶液与氯离子形成的氯化银悬浊液,暗置15min后,其在420nm波长下的吸光度保持稳定,且氯离子质量浓度在0.5~3μg/mL范围内符合比尔定律,方法的测定下限为0.002%。将方法应用于硫酸氧钒中氯的测定,结果与离子色谱法相符,相对标准偏差(RSD,n=8)小于5.0%,加标回收率在99%~102%之间。

After the vanadyl sulfate sample was treated by NaOH-H2O2,the acidity of the sample solution was adjusted by acetic acid and the vanadium in it was separated with precipitation by heating in boiling water bath.The content of chloride ion in the filtrate was then determined by silver nitrate turbidimetry.The effect of nitric acid amount,the addition amount of silver nitrate,and determination time,etc.was discussed to determine the optimal determination conditions.It was found that,after the silver chloride turbid liquid formed by silver nitrate and chloride ion was kept in dark for 15 min,the absorbance of chloride ion kept constant at420 nm,and the content of chloride ion obeyed Beer's law within the range of 0.5-3μg/mL.The limit of quantification was 0.002%.When the method was applied to determine chloride ion in vanadyl sulfate samples,the results were consistent with those obtained by ion chromatography.The relative standard deviation(RSD,n=8)was less than 5.0%and the standard addition recovery was 99%-102%.