Isolation of NO3−‐N as 1‐phenylazo‐2‐naphthol (Sudan‐1) for measurement of δ15N

The conversion of nitrate (NO(3)(-)) to 1-phenylazo-2-naphthol (Sudan-1) has been examined as a method for natural abundance measurement of delta(15)N of NO(3)(-). The reaction results in dilution of NO(3)(-)-N with only one reagent-derived N and the product is readily concentrated from dilute samples by reverse phase chromatography. There is systematic isotopic fractionation during the reaction, but this can be allowed for by analysing known NO(3)(-) standards along with each sample set. Sudan-1 prepared from surface water samples containing approximately 50 mg NO(3)(-)-N can be analysed by automated continuous flow isotope ratio mass spectrometry with a precision of 0.2 per thousand (one standard deviation) and the accuracy is not affected by interference from other nitrogenous species in the sample or reagents. Copyright 1999 John Wiley & Sons, Ltd.

[1]  Ueber das Cinchonin , 1879 .

[2]  R. Wetzel,et al.  A rapid Chromatographic method for recovery of 15NO2 and NO3‐ produced by nitrification in aqueous samples , 1992 .

[3]  P. Harrison,et al.  A note of caution on reduction conditions when using the cadmium-copper column for nitrate determinations in aquatic environments of varying salinities , 1992 .

[4]  G. Rieley.  Derivatization of organic compounds prior to gas chromatographic–combustion–isotope ratio mass spectrometric analysis: identification of isotope fractionation processes , 1994 .

[5]  G. Gong,et al.  The nitrogen isotopic composition of nitrate in the Kuroshio Water northeast of Taiwan: evidence for nitrogen fixation as a source of isotopically light nitrate , 1996 .

[6]  Nitrate analysis in biological fluids by gas chromatography-nitrogen-phosphorous detection. , 1996, Analytical biochemistry.

[7]  R. Michener,et al.  Natural abundance-level measurement of the nitrogen isotopic composition of oceanic nitrate: an adaptation of the ammonia diffusion method , 1997 .

[8]  C. Scrimgeour,et al.  Terrestrial plant ecology and 15N natural abundance : The present limits to interpretation for uncultivated systems with original data from a Scottish old field , 1997 .

[9]  K. Dittert,et al.  Improved diffusion technique for 15N:14N analysis of ammonium and nitrate from aqueous samples by stable isotope spectrometry , 1998 .

[10]  J. Conroy,et al.  A possible plant-mediated feedback between elevated CO2, denitrification and the enhanced greenhouse effect , 1998 .

[11]  Jae-E. Yang,et al.  A Simple Spectrophotometric Determination of Nitrate in Water, Resin, and Soil Extracts , 1998 .

[12]  T. Preston,et al.  Isotope Dilution Analysis of Combined Nitrogen in Natural Waters. III. Nitrate and nitrite , 1998 .