Determination of ¹⁵N abundance in nanogram pools of NO₃ ^- and NO₂ ^- by denitrification bioassay and mass spectrometry

TY - JOUR

T1 - Determination of 15N abundance in nanogram pools of NO3 - and NO2 - by denitrification bioassay and mass spectrometry

AU - Højberg, Ole

AU - Johansen, H. S.

AU - Sorensen, J.

PY - 1994/1/1

Y1 - 1994/1/1

N2 - Suspensions of two strains of Pseudomonas aeruginosa (ON12 and ON12-1) were used to reduce NO3 - and NO2 -, respectively, to N2O. The evolved N2O was quantified by gas chromatography with electron capture detection, and the 15N abundance was determined by mass spectrometry with a special inlet system and triple-collector detection. Sample gas containing unknown N2O pools as small as 0.5 ng of N was analyzed by use of a spike technique, in which a reference gas of N2O of natural 15N abundance was added to obtain enough total N for the mass spectrometer. In NO3 - or NO2 - pools, the 15N abundance could be determined in samples as small as approximately 3.5 ng of N. No cross-contamination took place between the NO3 - and NO2 - pools. The excellent separation of NO3 - and NO2 - pools, small sample size required, and low contamination risk during N2O analysis offer great advantages in isotope studies of inorganic N transformations by, e.g., nitrifying or denitrifying bacteria in the environment.

AB - Suspensions of two strains of Pseudomonas aeruginosa (ON12 and ON12-1) were used to reduce NO3 - and NO2 -, respectively, to N2O. The evolved N2O was quantified by gas chromatography with electron capture detection, and the 15N abundance was determined by mass spectrometry with a special inlet system and triple-collector detection. Sample gas containing unknown N2O pools as small as 0.5 ng of N was analyzed by use of a spike technique, in which a reference gas of N2O of natural 15N abundance was added to obtain enough total N for the mass spectrometer. In NO3 - or NO2 - pools, the 15N abundance could be determined in samples as small as approximately 3.5 ng of N. No cross-contamination took place between the NO3 - and NO2 - pools. The excellent separation of NO3 - and NO2 - pools, small sample size required, and low contamination risk during N2O analysis offer great advantages in isotope studies of inorganic N transformations by, e.g., nitrifying or denitrifying bacteria in the environment.

M3 - Journal article

AN - SCOPUS:0028181321

SN - 0099-2240

VL - 60

SP - 2467

EP - 2472

JO - Applied and Environmental Microbiology

JF - Applied and Environmental Microbiology

IS - 7

ER -