钙、镁、铁、铝离子对土壤中总氟化物检测干扰的消除  

Elimination of interference from calcium magnesium iron and aluminum ions in the detection of the total fluoride in soil

作　　者：徐荣[1] 孙娟[1] 叶瑾[1] XU Rong, SUN Juan, YE Jin(Nanjing Environmental Monitoring Center Station, Nanjing 210013, China)

机构地区：[1]南京市环境监测中心站,南京210013

出　　处：《化学分析计量》2018年第4期16-20,共5页Chemical Analysis And Meterage

基　　金：2009年环保部标准制修订项目资助项目(1071)

摘　　要：建立钙、镁、铁、铝离子对离子选择电极法检测土壤总氟化物干扰的消除方法。通过对含不同浓度水平钙、镁、铁、铝离子的土壤样品中总氟化物进行测试,明确了在总离子强度调节缓冲溶液共存下钙、镁、铁、铝离子对土壤提取液中总氟化物检测结果存在负干扰。通过测试10种土壤样品总氟化物提取液中干扰最强的背景铝含量,对其中土壤提取液中铝离子质量浓度大于10.0 mg/L的3种土壤样品进行加标回收试验,结果表明了土壤总氟化物含量为327～926 mg/kg范围内,当样品提取液中的铝离子含量为50～100 mg/L时,通过减少提取液取样体积为5.00 mL并增加柠檬酸三钠总离子强度缓冲溶液体积至15.0 mL的方法可将加标回收率由56.4%～78.3%优化至94.7%～104.0%;当加入Ca^(2+),Mg^(2+),Fe^(3+)质量浓度为200～300 mg/L,加标回收率由63.1%～77.6%优化为92.4%～105.0%。用优化后的方法测定土壤总氟化物含量为246～2 240 mg/kg的5种标准样品,测试结果与标准值一致。该方法能有效地消除土壤样品总氟化物测定中含钙、镁、铁离子质量浓度为200～300 mg/L,铝离子质量浓度为50～100 mg/L而产生的干扰,具有良好的适用性。The elimination method for interference of calcium, magnesium, iron and aluminum ions in the determination of total fluoride in soil with ion selective electrode method was established. The negative interference ability of the calcium, magnesium, iron and aluminum ions with the co-existing of total ionic strength regulation buffer solution was confirmed in the detection of total fluoride in soil by testing different levels of four kinds metal ions in the soil samples. The background content of aluminum that had strongest negative interference ability in the total fluoride extract of ten soil samples were measured and statistics. The three soil samples were selected for the standard addition recovery test because the aluminum content in the extraction solution was greater than 10.0 mg/L. Results showed that the total fluoride content in soil ranged from 327 mg/kg to 926 mg/kg and the samples of aluminum ion content was 50–100 mg/L in liquid extract, the standard addition recovery rate could be optimized from 56.4%–78.3% to 94.7%–104.0% by reducing the extract divide volume to 5.00 mL and increasing the volume of sodium citrate buffer solution to 15.0 mL; when the content of Ca2＋, Mg2＋, Fe3＋ was 200–300 mg/L, the recovery could be optimized from 63.1%–77.6% to 92.4%–105.0% by the same method. Five kinds of soil standard samples with total fluoride content of 246–2 240 mg/kg were determined by the optimized method, the results were consistent with standard values. The method can effectively eliminate interference in the determination of total fluoride in soil when the content of calcium, magnesium and iron ion is 200–300 mg/L, and that of aluminum is 50–100 mg/L. The method has good applicability.

关 键 词：钙、镁、铁、铝离子 总氟化物 离子选择电极法 干扰与消除 

分 类 号：O657.15[理学—分析化学]