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投稿时间:2022-03-23 修订日期:2022-03-27
投稿时间:2022-03-23 修订日期:2022-03-27
中文摘要: 土壤氮素在土壤养分供给和植物生长发育中起着重要作用。利用氮稳定同位素自然丰度或富集标记技术,开展土壤氮循环转化、化肥利用效率和生物有效性等方面的研究,涉及NH4+-N稳定同位素比值的精准测定。本研究在前人基础上,开发了一种快速高通量的铵态氮蒸馏分离方法,并使用次氯酸盐替代了次溴酸盐优化了铵态氮化学转化条件,将转化效率由原方法的25%左右,提高至60%以上。利用新建立的前处理方法结合气体预浓缩装置与稳定同位素质谱仪(PreCon-IRMS)联用系统,分析了不同浓度条件下自然丰度、15N富集和标记的NH4+-N标准溶液中的氮稳定同位素比值。结果表明,新的反应体系下,当铵态氮浓度为0.5 μmol /mL以上时,所有NH4+-N标准样品均能获得较理想的分析精度,其中自然丰度和15N富集参比溶液的NH4+-N的δ15N的精度可控制在0.5‰以内,而15N标记的标准溶液的15N atom%测试精度为0.001~0.006 atom%(CV在0.1~0.3%之间)。所有NH4+-N标准样品的15N测定值与参考值一致,无分馏现象发生。将该方法应用于两种不同土地类型的旱地和稻田土壤浸提液中NH4+-N稳定同位素丰度的测定,也可获得较好的重现性(CV<0.5%),与原方法测定结果基本一致,且精度更优。优化后的前处理方法操作简单,耗时短,重复性好,适用于土壤溶液铵态氮15N丰度测定的快速、批量前处理。
Abstract:Application of mineral fertilizers, especially N fertilizer, compensates the increase in plant demand of the growing population. Ammonium nitrogen (NH4+-N) plays an important role in soil N retention, nutrient supply and plant growth derived by microbial immobilization/mineralization and mineral fixation/release of ammonium. Therefore, the accurate determination of NH4+-N isotope ratios seemed critical for the studies on soil nitrogen cycling and transformation, fertilizer use efficiency and bioavailability, by using stable isotope natural abundance or enrichment labeling techniques. In this study, a rapid and high throughput ammonium-nitrogen distillation separation method was developed. Furthermore, the chemical conversion procedure of ammonium nitrogen was optimized by using hypochlorite instead of hypobromate. Finally, the conversion efficiency was increased from 25% to 60%. The 15N analysis of reference NH4 +-N solutions with different concentrations and 15N abundance was carried out by using the newly developed method combined with the PreCon-IRMS system. The results showed that, in the new reaction system, the detection limit was as low as 0.5 μmol mL-1, and the accuracy of δ15N of the natural abundance and enriched labeled N reference solution (NH4+-N) were within 0.5‰ for δ15N and 0.01% atom for 15N atom%, respectively. At the same time, the 15N abundance in ammonium nitrogen extracted from different soils were determined by the new method as compared with the previous method. The comparison of the analytical data from the two analytical systems indicates that the new method provides better nitrogen stable isotope data in reproducibility and accuracy(CV<0.5%)than the data from the previous method. Overall, our method has the advantages of being rapid, convenient, and applicable to N stable isotope ratio determination in soil ammonium nitrogen.
keywords: soil ammonium nitrogen nitrogen isotope isotope ratio mass spectrometry (IRMS) distillation chemical conversion N2O method hypochlorite
文章编号: 中图分类号: 文献标志码:
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
作者 | 单位 | |
袁红朝* | 中国科学院 | yuanhongzhao@isa.ac.cn |
贺珍 | 中国科学院 | hezhen@isa.ac.cn |
张丽萍 | 中国科学院 | zlpeap@isa.ac.cn |
王久荣 | 中国科学院 | jrwang@isa.ac.cn |
引用文本:
袁红朝,贺珍,张丽萍,王久荣.土壤铵态氮中氮稳定同位素比值测定前处理方法优化研究[J].中国无机分析化学,2023,13(2):129-135.
YUAN Hong-zhao,HE Zhen,ZHANG Li-ping,WANG Jiu-rong.Optimization of Pretreatment Methods for Nitrogen Stable Isotope Ratio Analysis in Soil Ammonium Nitrogen[J].Chinese Journal of Inorganic Analytical Chemistry,2023,13(2):129-135.
袁红朝,贺珍,张丽萍,王久荣.土壤铵态氮中氮稳定同位素比值测定前处理方法优化研究[J].中国无机分析化学,2023,13(2):129-135.
YUAN Hong-zhao,HE Zhen,ZHANG Li-ping,WANG Jiu-rong.Optimization of Pretreatment Methods for Nitrogen Stable Isotope Ratio Analysis in Soil Ammonium Nitrogen[J].Chinese Journal of Inorganic Analytical Chemistry,2023,13(2):129-135.