Molecular oxygen (O2) has been documented to ionize partially to NO+ in mass spectrometer sources, generating a signal that overlaps with that of 15N2 (mass-to-charge of 30). Here, we tested whether O2 needs to be specifically removed from the sample streams of the Membrane Inlet Mass Spectrometer and the Isotope Ratio Mass Spectrometer in order to properly quantitate 15N2 atom% at pertinent concentrations. Sample streams with and without O2 yielded similar signals, suggesting that O2 does not interfere with the 15N2 atom% measurements in the experimental range with the given instruments.

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Archival Copy

Version Date	Archive	Persistent Identifier (PID)	Date PID Issued
2019-10-02	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.1575/1912/bco-dmo.778083.1	2020-01-06

Description

Test of potential m/z 30 interferences from O2

Methods & Sampling

The measurements presented here were conducted with a MIMS and an IRMS each equipped with high-temperature copper reduction columns to scrub O2 from the gas stream entering the source. However, samples measured in parallel on the IRMS and on the MIMS without the O2 scrubbing column yielded similar 15N atom % values, indicating that any NO+ generated in the respective IRMS and MIMS sources was insufficient to alter the 15N atom % significantly in the range pertinent to 15N2 tracer incubations.

Data Processing Description

BCO-DMO Processing Notes:
- table was extracted from original spreadsheet.
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions

Data Files

File
mz_30_int_from_o2.csv (Comma Separated Values (.csv), 4.11 KB) MD5:5eea994368a25b2fb14d33d9c1b2a749 Primary data file for dataset ID 778083

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1732246

Deployments

None available yet

Instruments

Isotope-ratio Mass Spectrometer

Supplied Name: Isotope Ratio Mass Spectrometer

Supplied Description:

continuous flow Delta V Isotope Ratio Mass Spectrometer (Smith et al. 2015), and continuous flow-GV Isoprime IRMS (Charoenpong et al., 2014)

Instrument Type

Generic Name: Isotope-ratio Mass Spectrometer

Acronym: IR Mass Spec; IRMS

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB16/

Generic Description:

The Isotope-ratio Mass Spectrometer is a particular type of mass spectrometer used to measure the relative abundance of isotopes in a given sample (e.g. VG Prism II Isotope Ratio Mass-Spectrometer).

Membrane Inlet Mass Spectrometer

Supplied Description:

Membrane Inlet Mass Spectrometer (Bay Instruments)

Instrument Type

Generic Name: Membrane Inlet Mass Spectrometer

Acronym: MIMS

Generic Description:

Membrane-introduction mass spectrometry (MIMS) is a method of introducing analytes into the mass spectrometer's vacuum chamber via a semipermeable membrane.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
Sample	sample	unitless	no_bcodmo_term
Time_of_analysis	time the analysis was conducted in 24 hour format	unitless	no_bcodmo_term
m_z_28	mass-to-charge	unitless	no_bcodmo_term
m_z_29	mass-to-charge	unitless	no_bcodmo_term
m_z_30	mass-to-charge	unitless	no_bcodmo_term
m_z_32	mass-to-charge	unitless	no_bcodmo_term
m_z_40	mass-to-charge	unitless	no_bcodmo_term
N2_Ar	N2/Ar ratio	unitless	no_bcodmo_term
ratio_28_29	28/29 ratio	unitless	no_bcodmo_term
ratio_28_30	28/30 ratio	unitless	no_bcodmo_term
atom_pcnt_15n	15 N atom %	unitless	no_bcodmo_term
Notes	additional comments	unitless	no_bcodmo_term

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Database

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Dataset: mz_30_int_from_o2

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Database

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Dataset: mz_30_int_from_o2

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