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投稿时间：2011-08-16 修订日期：2011-09-27
投稿时间：2011-08-16 修订日期：2011-09-27
中文摘要: 食品和环境样品中往往同时含有硝酸根和碘离子，用紫外分光光度法直接测定硝酸根或碘离子时，二者相互干扰。为此建立了主、次波长分别为220.0、231.5 nm的等吸收点双波长紫外分光光度法测定溶液中的硝酸根和共存的碘离子。当溶液中硝酸根的浓度范围在0~0.12 mmol/L，碘离子的浓度在0~0.10 mmol/L时，主、次波长下的吸光度差值A220-231.5与溶液中硝酸根的浓度 呈良好线性关系，线性方程为A220-231.5= 2.9958 + 0.0016（R2 = 0.99994）；其中A220 (NO3-) = 3.6099 + 0.0084（R2 = 0.99994），利用吸光度的加和性：A220 (I-) =A220-A220 (NO3-)= 10.7394 + 0.0029（R2 = 0.99994），间接得到碘离子含量 。硝酸根和碘离子的平均相对标准偏差分别为0.6%、0.2%，回收率分别为99.5%~102%、99.9%~100%。方法简便快捷，可用于溶液中微量硝酸根和碘离子的同时测定。
Abstract:Nitrate and iodide ions are usually coexisted in environmental and food samples. When the contents of nitrate or iodide ions are determined directly using UV spectrophotometry, the interference between the two kinds of ions will occur. Therefore, in this study, isobestic point dual-wavelength spectrophotometry with primary and secondary wavelengths of 220.0 and 231.5 nm was used to simultaneously determine trace nitrate ions and coexisting iodide ions in solutions. When the nitrate concentration is in the range of 0~0.12 mmol/L, and the iodide concentration is in the range of 0~0.10 mmol/L, there is a liner relationship between absorbance difference A220-231.5 and nitrate concentration which can be described by the equation of A220-231.5= 2.9958 +0.0016 (R2 = 0.99994). Iodide ion concentration can be indirectly detected based on the additivity of the absorbance described by the equations of A220 (I-) = A220- A220 (NO3-) = 10.7394CI - +0.0029(R2=0.99994) and A220(NO3-)=3.6099 +0.0084(R2 = 0.99994). The relative standard deviation of the analysis method is 0.6% for nitrate ion and 0.2% for iodide ion, and the recovery is 99.5%~102% for nitrate ion and 99.9%~100% for iodide ion, respectively. The method was proved to be convenient and reliable for simultaneous determination of trace nitrate and iodide ions in aqueous solutions.
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基金项目:国家自然科学基金（50972151，51002164）；中国科学院西部行动计划项目（KZCX2-XB3-06）；中国科学院“西部之光”人才培养项目（科发人教字2009（236）号）
| 作者 | 单位 |
| 张慧芳 | 1.中国科学院青海盐湖研究所，西宁 810008；2 中国科学院研究生院，北京 100049 |
| 郭 探 | 1.中国科学院青海盐湖研究所，西宁 810008；2 中国科学院研究生院，北京 100049 |
| 李 权 | 中国科学院青海盐湖研究所，西宁 810008 |
| 叶秀深 | 中国科学院青海盐湖研究所，西宁 810008 |
| 吴志坚 | 中国科学院青海盐湖研究所，西宁 810008 |
引用文本：
张慧芳,郭 探,李 权,叶秀深,吴志坚.双波长分光光度法同时测定溶液中的硝酸根和碘离子[J].中国无机分析化学,2011,1(4):24-28.
ZHANG Huifang,GUO Tan,LI Quan,YE Xiushen,WU Zhijian.Simultaneous Determination of Nitrate and Iodide Ions in Aqueous Solutions by Dual-wavelength Spectrophotometry[J].Chinese Journal of Inorganic Analytical Chemistry,2011,1(4):24-28.
张慧芳,郭 探,李 权,叶秀深,吴志坚.双波长分光光度法同时测定溶液中的硝酸根和碘离子[J].中国无机分析化学,2011,1(4):24-28.
ZHANG Huifang,GUO Tan,LI Quan,YE Xiushen,WU Zhijian.Simultaneous Determination of Nitrate and Iodide Ions in Aqueous Solutions by Dual-wavelength Spectrophotometry[J].Chinese Journal of Inorganic Analytical Chemistry,2011,1(4):24-28.
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