Determination of N-15-labeled ammonium and total nitrogen in plant and fungal systems using mass-spectrometry

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Determination of N-15-labeled ammonium and total nitrogen in plant and fungal systems using mass-spectrometry. / Ek, H.; Finlay, R.D.; Söderström, Bengt; Odham, G.

In: Journal of Microbiological Methods, Vol. 11, No. 3-4, 1990, p. 169-176.

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TY - JOUR

T1 - Determination of N-15-labeled ammonium and total nitrogen in plant and fungal systems using mass-spectrometry

AU - Ek, H.

AU - Finlay, R.D.

AU - Söderström, Bengt

AU - Odham, G.

PY - 1990

Y1 - 1990

N2 - A selected ion-monitoring method to measure 15N-labelled ammonia in biological samples was improved to simplify sample handling, to obviate interference from ammonia due to the decomposition of glutamine and to allow the determination of total N. Ammonia is derivatized with pentafluorobenzoylchloride to yield pentafluorobenzamide which is analysed by gas chromatography/mass spectrometry after clean-up using disposable silicic acid columns. The sensitivity achieved when operating in the negative ion-chemical ionization mode was somewhat higher than when using electron-impact ionization. Use of methyl amine as an internal standard improved the accuracy and precision of the measurements. The method was applied to samples taken from an intact ectomycorrhizal system fed with ISN-labelled ammonium and used to determine patterns of N assimilation into ammonium, free amino acids and macromolecular compounds.

AB - A selected ion-monitoring method to measure 15N-labelled ammonia in biological samples was improved to simplify sample handling, to obviate interference from ammonia due to the decomposition of glutamine and to allow the determination of total N. Ammonia is derivatized with pentafluorobenzoylchloride to yield pentafluorobenzamide which is analysed by gas chromatography/mass spectrometry after clean-up using disposable silicic acid columns. The sensitivity achieved when operating in the negative ion-chemical ionization mode was somewhat higher than when using electron-impact ionization. Use of methyl amine as an internal standard improved the accuracy and precision of the measurements. The method was applied to samples taken from an intact ectomycorrhizal system fed with ISN-labelled ammonium and used to determine patterns of N assimilation into ammonium, free amino acids and macromolecular compounds.

KW - Ammonia

KW - Ectomycorrhiza

KW - Mass spectrometry

KW - 15N

KW - N assimilation

M3 - Article

VL - 11

SP - 169

EP - 176

JO - Journal of Microbiological Methods

JF - Journal of Microbiological Methods

SN - 1872-8359

IS - 3-4

ER -