【摘要】 氯离子（Cl^-）测定在研究氯营养和盐胁迫过程中起着关键作用，但是样品的预处理仍然是检测Cl^-的一个难题，针对植物、土壤、肥料、水体并没有统一的样品预处理方法。基于硝酸银（AgNO₃）滴定法测定Cl^-的机理，研究过氧化氢（H₂O₂）预处理样品测定Cl^-的原理和方法。结果表明，H₂O₂在非浓盐酸环境下不能氧化Cl^-而生成氯气（Cl₂）;H₂O₂电离出的氢离子（H⁺）会与Cl^-结合生成氯化氢（HCl），在加热条件下挥发导致Cl^-损失；H₂O₂和试样在加热回流冷凝条件下可对样品进行脱色和有机物降解，既不会造成Cl^-损失，又利于后续滴定终点判断；H₂O₂预处理方法适用于植物、土壤和浑浊水样中Cl^-的测定；该方法具有操作简单、无二次污染、测定结果准确度和精密度高等优点。为建立不同基质样品中Cl^-检测的统一标准测试方法奠定了理论和实践基础。更多还原

【Abstract】 The determination of chloride ions（Cl^-） plays a crucial role in studying chloride nutrition and salt stress processes.However,the sample preparation remains a challenge in detecting Cl^-,and there is no unified method for plant,soil,fertilizer and water samples.Based on the mechanism of silver nitrate（AgNO₃） titration for Cl^- determination,the mechanism and method of using hydrogen peroxide（H₂O₂） for sample pretreatment was investigated.The results showed that H₂O₂,in a non-concentrated acid environment,could not oxidize Cl^- to chlorine gas（Cl₂）.The hydrogen ions（H⁺）produced from the ionization of H₂O₂ could combine with Cl^- to form hydrogen chloride（HCl）,which volatilized under heating conditions,leading to loss of Cl^-.The sample could be pretreated using H₂O₂ under heating reflux and condensation conditions,which not only prevented loss of Cl^- but also facilitated subsequent determination of titration end point.The H₂O₂ pretreatment method was suitable for determination of Cl^- in plants,soil and turbid water samples.This method had the advantages of simple operation,no secondary pollution,high accuracy and precision of measurement results.This study established a theoretical and practical foundation for developing a unified standard testing method for Cl^- in different matrix samples.更多还原