These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Determination of nitrate and nitrite in freshwaters using flow-injection with luminol chemiluminescence detection.
    Author: Yaqoob M, Folgado Biot B, Nabi A, Worsfold PJ.
    Journal: Luminescence; 2012; 27(5):419-25. PubMed ID: 23044772.
    Abstract:
    A simple and sensitive flow-injection (FI) method for the determination of nitrate and nitrite in natural waters, based on luminol chemiluminescence (CL) detection, is reported. Nitrate was reduced online to nitrite via a copperized cadmium (Cu-Cd) column and then reacted with acidic hydrogen peroxide to form peroxynitrous acid. CL emission was observed from the oxidation of luminol in an alkaline medium in the presence of the peroxynitrite anion. The limits of detection (S:N = 3) were 0.02 and 0.01 µg N/L, with sample throughputs of 40 and 90 /h for nitrate and nitrite, respectively. Calibration graphs were linear over the range 0.02-50 and 0.01-50 µg N/L [R2  = 0.9984 (n = 8) and R2  = 0.9965 (n = 7)] for nitrate and nitrite, respectively, with relative standard deviations (RSDs; n = 3) in the range 1.8-4.6%. The key chemical and physical variables (reagent concentrations, buffer pH, flow rates, sample volume, Cu-Cd reductor column length) were optimized and potential interferences investigated. The effect of cations [Ca(II), Mg(II), Co(II), Fe(II) and Cu(II)] was masked online with EDTA. Common anions (PO4(3-) , SO4(2-) and HCO3-) did not interfere at their maximum admissible concentrations in freshwaters. The effect of salinity on the luminol CL reaction with and without nitrate and nitrite (2 and 0.5 µg N/L, respectively) was also investigated. The method was successfully applied to freshwaters and the results obtained were in good agreement with those obtained by an automated segmented flow analyser reference method.
    [Abstract] [Full Text] [Related] [New Search]