USGS-GD-Scientific Capabilities - STABLE ISOTOPES NITROGEN 15 Technique

STABLE ISOTOPES

NITROGEN 15

Technique

 
  • Element:
Nitrogen delta 15N (atmospheric)
  • Material:
    • N2 and NH3 gas
    • Aqueous nitrate, nitrite, ammonium
    • Cyanide and mine drainage
    • Organic nitrogen
    • Nitrogen minerals (buddingtonite, ammonium illite, etc.)
    • Synthetic/agricultural chemicals
    • Explosives (TNT)
  • Form:
Extract and process to nitrogen, analyze N2 on mass spectrometer.
  • Precision:
Typically ±0.04 to 0.1 per mil
  • Applications:
Sources, tracers, and reaction pathways, biogeochemistry.
  • Instruments:
Finnigan 252, VG Optima
  • Speciality Peripherals:
Extraction lines, auto trapping/gas separation, VG multi-element analyzer, gas chromatograph with capillary, open-split interface to IRMS
  • Automation:
Yes ­ VG multi-element analyzer (~100/day)
  • Sample Size:
    • minimum: 1 nanomole as N2 extracted from sample
    • typical: 20-60 micromole as N2

 


 | Capabilities |
| Geochronology, Geochemistry, and Tracer Studies  |
| Geochemistry, and Tracer Studies  |

 


URL http://geology.cr.usgs.gov/capabilities/gronemtrac/geochem/stablei/nitrogen/tech.html