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| A gas phase conversion-chemiluminescence method for detecting nitrite concentrations in soils |
| Received:February 28, 2017 |
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| KeyWord:nitrite;chemiluminescence;soil;nitric oxide |
| Author Name | Affiliation | E-mail | | WANG Lin | College of Resources and Environmental Sciences, Agricultural University of Hebei, Baoding 071000, China
State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China | | | WANG Rui | State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China | wangrui@mail.iap.ac.cn | | ZHENG Xun-hua | State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
College of Earth Sciences, University of Chinese Academy of Sciences, Beijing 200049, China | | | ZHANG Li-juan | College of Resources and Environmental Sciences, Agricultural University of Hebei, Baoding 071000, China | |
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| Abstract: |
| A chemiluminescence method that detects nitric oxide(NO) combined with the conversion from nitrite to NO for measuring soil nitrite concentrations is reported. The applicability of the method is evaluated by comparing it with the colorimetry method. The chemiluminescence method involves a reaction system consisting of 50% glacial acetic acid and ascorbic acid in the purge vessel. At room temperature, samples containing nitrite were injected into the purge vessel and nitrite was stoichiometrically reduced to NO by ascorbic acid under these acidic conditions. The produced NO was swept with pure nitrogen gas into the NO analyzer and the data was recorded while chemiluminescence signals were generated. The concentration of nitrite in the samples was calculated by the curve between the peak areas of the NO signals and the corresponding standard nitrite concentrations. The results showed that peak areas of chemiluminescence signals were linearly positively correlated with the nitrite concentrations in the range of 2 to 500 μg·L-1(P<0.01). The lowest detection limit of this method was 2 μg·L-1, equivalent to10 μg·kg-1 in soil(water:soil=5:1), lower than that of the colorimetry method(15 μg·kg-1). This method had a good precision of 1.2 μg·L-1 within 95% confidence interval by repeating the measurements of standard nitrite concentration of 50 μg·L-1 for ten times. The corresponding precision for soil nitrite concentration(6 μg·kg-1) was also better than that of colorimetry(11 μg·kg-1). The recovery rates were in the range of 90%~97%. Compared to the colorimetry, the chemiluminescence method had the same accuracy for detecting nitrite concentrations in acid soils, but it overestimated the concentrations in alkaline soil because of the existence of Ca2+, SO42-, and CO32- in alkaline soil. Moreover, the analysis times for each soil nitrite sample were approximately 8~15 min, which is time-consuming comparing to the colorimetry method. |
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