title: A rapid and high-throughput microplate spectrophotometric method for field measurement of nitrate in seawater and freshwater.
abstract: The well-known zinc-cadmium reduction method is frequently used for determination of nitrate. However, this method is seldom to be applied on field research of nitrate due to the long time consuming and large sample volume demand. Here, we reported a modified zinc-cadmium reduction method (MZCRM) for measurement of nitrate at natural-abundance level in both seawater and freshwater. The main improvements of MZCRM include using small volume disposable tubes for reaction, a vortex apparatus for shaking to increase reduction rate, and a microplate reader for high-throughput spectrophotometric measurements. Considering salt effect, two salinity sections (5~10 psu and 20~35 psu) were set up for more accurate determination of nitrate in low and high salinity condition respectively. Under optimized experimental conditions, the reduction rates were stabilized on 72% and 63% on the salinity of 5 and 20 psu respectively. The lowest detection limit for nitrate was 0.5 μM and was linear up to 100 μM (RSDs was 4.8%). Environmental samples assay demonstrated that MZCRM was well consistent with conventional zinc-cadmium reduction method. In total, this modified method improved accuracy and efficiency of operations greatly, and would be realized a rapid and high-throughput determination of nitrate in field analysis of nitrate with low cost.
authors.affiliation: State Key Laboratory of Tropical Oceanography (LTO), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, P. R. China.|University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
authors.forename: Jiapeng
authors.initials: J
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Tropical Oceanography (LTO), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, P. R. China.
authors.forename: Yiguo
authors.initials: Y
authors.lastname: Hong
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510090, P. R. China.
authors.forename: Fengjie
authors.initials: F
authors.lastname: Guan
authors.affiliation: State Key Laboratory of Tropical Oceanography (LTO), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, P. R. China.|University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, P. R. China.
authors.forename: Yehui
authors.initials: Y
authors.lastname: Tan
authors.affiliation: State Key Laboratory of Tropical Oceanography (LTO), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, P. R. China.
authors.forename: Weizhong
authors.initials: W
authors.lastname: Yue
authors.affiliation: State Key Laboratory of Tropical Oceanography (LTO), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, P. R. China.
authors.forename: Meilin
authors.initials: M
authors.lastname: Wu
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510090, P. R. China.
authors.forename: Liying
authors.initials: L
authors.lastname: Bin
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510090, P. R. China.
authors.forename: Jiaping
authors.initials: J
authors.lastname: Wang
authors.affiliation: School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510090, P. R. China.
authors.forename: Jiali
authors.initials: J
authors.lastname: Wen
mesh_terms: D002104:Cadmium / Q000737:chemistry; D002138:Calibration; D005618:Fresh Water / Q000737:chemistry*; D057166:High-Throughput Screening Assays / Q000295:instrumentation* / Q000379:methods*; D057230:Limit of Detection; D009566:Nitrates / Q000032:analysis*; D010084:Oxidation-Reduction; D012015:Reference Standards; D015203:Reproducibility of Results; D054712:Salinity; D012623:Seawater / Q000737:chemistry*; D013053:Spectrophotometry / Q000295:instrumentation* / Q000379:methods*; D013997:Time Factors; D015032:Zinc / Q000737:chemistry
chemical_list: D009566:Nitrates; D002104:Cadmium; D015032:Zinc
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