| 柱后衍生离子色谱法测定土壤和沉积物中的六价铬 |
| Determination of Hexavalent Chromium in Soil and Sediment by Heating Reflux and Post-Column Derivatization Ion Chromatography |
| 投稿时间：2022-04-27 修订日期：2023-05-09 |
| DOI：10.19316/j.issn.1002-6002.2023.05.24 |
| 中文关键词: 六价铬 土壤和沉积物 加热回流提取 柱后衍生 离子色谱 |
| 英文关键词:hexavalent chromium soil and sediment heating reflux post-column derivatization ion chromatography |
| 基金项目: |
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| 通讯作者:朱红霞* 中国环境监测总站, 国家环境保护环境监测质量控制重点实验室, 北京 100012 |
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| 中文摘要: |
| 采用加热回流提取、柱后衍生离子色谱法分离土壤和沉积物中的六价铬，使用紫外可见检测器进行测定。选用7种土壤和沉积物的实际样品，依次讨论了氢氧化钠-碳酸钠溶液、碳酸氢钠溶液、氢氧化钠-氯化钾溶液、离子色谱碱性淋洗液4种不同提取剂对六价铬的提取效率，以及超声提取、水浴振荡提取和恒温磁力搅拌冷凝回流3种提取方式的提取效果；研究了10~60 min、25~190℃条件下的最佳提取时间和加热温度；分析了不同提取剂体积和称样量比值条件下六价铬标土的测定量，并探究了提取液的保存条件。优化后的前处理条件：称取2.5 g筛分后的土壤或沉积物样品，加入25 mL NaOH/Na2CO3提取剂，在恒温磁力搅拌冷凝回流装置上于120℃加热回流60 min，离心后用0.22 μm滤膜过滤，用柱后衍生离子色谱紫外检测装置进行测定。相比目前常用的分光光度法、原子吸收法等测定土壤中六价铬方法，柱后衍生离子色谱法特异性强，降低了差减法或其他前处理技术测定六价铬时所引入的误差，且不受提取液色度、浊度等影响。方法检出限可达0.002 mg/kg，灵敏度高，操作简便，抗干扰能力强，对于低含量土壤和沉积物样品的测定更具优势，可满足土壤和沉积物中低含量六价铬的测定需求。 |
| 英文摘要: |
| Heated and refluxed extraction-post-column derivatized ion chromatography was used to separate hexavalent chromium in soil and sediment,and UV-visible detector was used for determination.Using 7 kinds of soil and sediments actual samples,the effects of 4 different extractants on hexavalent chromium were discussed,including sodium hydroxide-sodium carbonate solution,sodium bicarbonate solution,sodium hydroxide-potassium chloride solution,and ion chromatography alkaline eluent.Extraction effect of 3 extraction methods were discussed,including ultrasonic extraction,water bath shaking extraction and constant temperature magnetic stirring condensation reflux.The optimal extraction time and temperature under the conditions of 10-60 min and 25-190℃ were studied.The determination of hexavalent chromium standard soil under the condition of different ratio of extract volume to sample weight was investigated,and the storage conditions of extracting solution were explored.The optimized pretreatment conditions were as follows:2.5 g sieved soil or sediment samples,add 25 mL of NaOH/Na2CO3 extractant,heat and reflux at 120℃ for 60 min,and filter through a 0.22 μm filter after centrifugation,and determined by post-column derivatized ion chromatography UV detection device.Compared with the commonly methods such as spectrophotometry and atomic absorption method for the determination of hexavalent chromium in soil and sediment,the post-column derivatized ion chromatography has strong specificity,which reduces the error introduced by the subtraction method or other pretreatment techniques for the determination of hexavalent chromium,and is not affected by the chromaticity and turbidity.The detection limit can reach 0.002 mg/kg,with high sensitivity,simple operation and strong anti-interference ability.It is more advantageous for the determination of low-content soil and sediment samples,and can meet the needs for the determination of low-content hexavalent chromium in soil and sediment. |
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