... C., and McDonnell, J.J., eds.). Elsevier,Amsterdam, pp. 87 118.Johnston, A.M., Scrimgeour, C.M., Henry, M.O., and Handley, L.L. 1999. Isolationof NO3-N as 1-phenylazo-2-naphthol (Sudan-1) ... (including soil extracts) for15N determination. NO3is converted to 1-phenylazo-2-naphthol (Sudan-1), and the product is concentrated by reverse-phase chromatography beforeCF-IRMS. The ... nitrogen, and oxygen isotope ratios of CH4 and N2O in soil ecosystems. In Mass Spectrometry of Soils (Boutton, T.W., and Yamasaki, S., eds.). Marcel Dekker, New York, pp. 177 –204.430 Scrimgeour and...