An ion chromatographic method with post-column derivatization and spectrophotometric detection is presented for the determination of nitrate and nitrite (NOx) in baby food. NOx residues found naturally or added as preservatives were extracted from baby foods and determined by using ion chromatography with post-column derivatization and spectrophotometric detection. Nitrate was reduced to nitrite online by post-column reduction using vanadium(lll) chloride and heat. Nitrite reacted with Griess reagent to produce a dye that was detected at 525 nm. The use of V(III) and heat to promote the reduction of nitrate to nitrite online is a novel feature of this detection system. The determination of incurred NOx residues in samples by using AOAC Method 993.03 yielded results comparable to those obtained by ion chromatography with spectrophotometric detection. The toxic and carcinogenic metal cadmium used in the AOAC Method to reduce the nitrate to nitrite was avoided. The proposed method provides simultaneous determination of nitrate and nitrite. Average recoveries of nitrate and nitrite residues ranged from 82 to 107% for fortification levels of 25-400 ppm.
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Environ Sci Technol
January 2025
Marine Synthetic Ecology Research Center, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Observation and Research Station for Marine Ranching in Lingdingyang Bay, China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Zhuhai 519082, China.
Plants can recruit microorganisms to enhance soil arsenic (As) removal and nitrogen (N) turnover, but how microbial As methylation in the rhizosphere is affected by N biotransformation is not well understood. Here, we used acetylene reduction assay, gene amplicon, and metagenome sequencing to evaluate the influence of N biotransformation on As methylation in the rhizosphere of , a potential As hyperaccumulator. was grown in mining soils (MS) and artificial As-contaminated soils (AS) over two generations in a controlled pot experiment.
View Article and Find Full Text PDFSmall
January 2025
Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, Delhi, 110016, India.
Crystalline γ-FeO(OH) dominantly possessing ─OH terminals (𝛾-FeO(OH)), polycrystalline γ-FeO(OH) containing multiple ─O, ─OH, and Fe terminals (𝛾-FeO(OH)), and α-FeO majorly containing ─O surface terminals are used as electrocatalysts to study the effect of surface terminals on electrocatalytic nitrate reduction reaction (eNORR) selectivity and stabilization of reaction intermediates. Brunauer-Emmett-Teller analysis and electrochemically determined surface area suggest a high active surface area of 117.79 m g (ECSA: 0.
View Article and Find Full Text PDFWater Res X
May 2025
School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, China.
Anaerobic ammonia oxidation (anammox) which converts nitrite and ammonium to dinitrogen gas is an energy-efficient nitrogen removal process. One of the bottlenecks for anammox application in wastewater treatment is the stable supply of nitrite for anammox bacteria. Dissimilatory nitrate reduction to ammonium (DNRA) is a process that converts nitrate to nitrite and then to ammonium.
View Article and Find Full Text PDFUnlabelled: The intestinal diarrheal pathogen colonizes the host terminal ileum, a microaerophilic, glucose-poor, nitrate-rich environment. In this environment, respires nitrate and increases transport and utilization of alternative carbon sources via the cAMP receptor protein (CRP), a transcription factor that is active during glucose scarcity. Here we show that nitrate respiration in aerated cultures is under control of CRP and, therefore, glucose availability.
View Article and Find Full Text PDFJ Environ Qual
January 2025
Institute for the Environment, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Population growth in coastal areas increases nitrogen inputs to receiving waterways and degrades water quality. Wetland habitats, including floodplain forests and marshes, can be effective nitrogen sinks; however, little is known about the effects of chronic point source nutrient enrichment on sediment nitrogen removal in tidally influenced coastal systems. This study characterizes enrichment patterns in two tidal systems affected by wastewater treatment facility (WWTF) effluent and assesses the impact on habitat nitrogen removal via denitrification.
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