Simultaneous underway analysis of nitrate and nitrite in estuarine and coastal waters using an automated integrated syringe-pump-based environmental-water analyzer
| Autor: | Jixin Chen, Nengwang Chen, Kunning Lin, Yiyong Jiang, Dongxing Yuan, Peicong Li, Tengyue Fang, Jian Ma |
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| Rok vydání: | 2019 |
| Předmět: |
Detection limit
Cadmium medicine.diagnostic_test Calibration curve 010401 analytical chemistry chemistry.chemical_element 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Biochemistry 0104 chemical sciences Analytical Chemistry Dilution chemistry.chemical_compound chemistry Nitrate Griess test Spectrophotometry Environmental chemistry medicine Environmental Chemistry Nitrite 0210 nano-technology Spectroscopy |
| Zdroj: | Analytica Chimica Acta. 1076:100-109 |
| ISSN: | 0003-2670 |
| DOI: | 10.1016/j.aca.2019.05.036 |
| Popis: | Methods for determining nitrate and nitrite have been comprehensively developed. However, there are few studies of simultaneous shipboard high-frequency monitoring of these two nutrients in estuarine and coastal area. In this study, a multipurpose integrated syringe-pump-based environmental-water analyzer (iSEA) was combined with an on-line filtration system for underway analysis of nitrate and nitrite in saline samples. Vanadium chloride was used instead of a toxic cadmium column to reduce nitrate to nitrite, which was measured on the basis of the classic Griess reaction. This fully automated analyzer had a limit of detection of 0.02 μmol L−1 for nitrite and 0.14 μmol L−1 for nitrate. The sample throughput was 12 h−1 for simultaneous measurement of nitrite and nitrate. With automated dilution, the calibration curve for nitrate was linear up to a concentration of 400 μmol L−1 (R2 > 0.999). The relative standard deviation of 24-h measurement (n = 288) of nitrite is 0.92% and that of nitrate is 1.4%. Both the reference solutions and samples of different salinities (range of 0–35) were measured (n = 85). According to the statistical t-test (P = 0.95), the results were insignificantly different from the results obtained using the reference method. After several cruise tests, the analyzer showed excellent spatial resolution for underway analysis of nitrite and nitrate in estuarine and coastal waters. |
| Databáze: | OpenAIRE |
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