Details zur Publikation

Kategorie Textpublikation
Referenztyp Zeitschriften
DOI 10.1016/j.watres.2005.02.017
Titel (primär) Modification of a continuous flow method for analysis of trace amounts of nitrate in iron-rich sediment pore-waters of mine pit lakes
Autor Herzsprung, P.; Duffek, A.; Friese, K.; de Rechter, M.; Schultze, M.; von Tümpling, W. ORCID logo
Quelle Water Research
Erscheinungsjahr 2005
Department SEEFO; FLOEK
Band/Volume 39
Heft 9
Seite von 1887
Seite bis 1895
Sprache englisch
Keywords Continuous flow analysis; Nitrate; Iron; Mine pits; Pore-water
Abstract Nitrate was analysed in pore-waters with high ionic strength. Extremely high concentrations of dissolved ferrous iron interfere common analytical methods. The automatic photometrical procedure based on the cadmium reduction method is often used for analysis of nitrate in water samples (continuous flow analysis CFA). An integrated dialysis usually serves for sample dilution and (or) sample purification (from particles). Iron was precipitated as iron hydroxide due to the imidazole buffer system (pH 7.5). The dialysis membrane is an effective barrier for iron hydroxide particles to prevent interferences within the cadmium column or the flow-cell. However, dialysis membrane is blocked successively after analysis of several iron-rich pore-water samples by agglomeration of precipitated iron. The blocking of nitrate diffusion through the dialysis membrane is tantamount to a decrease of analytical sensitivity to recognise by decreasing photometrical extinction. Minimising the iron deposition within the dialyser solved the problem. A simple modification of the CFA apparatus was found to keep the analytical sensitivity nearly constant: The mixing coil for the imidazole buffer was considerably elongated. Nearly all iron hydroxide was deposited at the glass coil surface installed before the dialyser. At least 50 iron-rich samples could be analysed within one sample queue with a loss of sensitivity <10%. The recovery of nitrate was about 95%, demonstrated by spiking experiments.
dauerhafte UFZ-Verlinkung https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=3443
Herzsprung, P., Duffek, A., Friese, K., de Rechter, M., Schultze, M., von Tümpling, W. (2005):
Modification of a continuous flow method for analysis of trace amounts of nitrate in iron-rich sediment pore-waters of mine pit lakes
Water Res. 39 (9), 1887 - 1895 10.1016/j.watres.2005.02.017