Comparison of procedures for reducing cross-contamination during steam distillations in nitrogen-15 tracer research

Journal Article · · Soil Sci. Soc. Am. J.; (United States)

OSTI ID:7190787

Mulvaney, R L

A study was conducted to compare the effectiveness of various procedures for reduction of cross-contamination errors when unenriched samples of (NH/sub 4/)/sub 2/SO/sub 4/ containing 0.5 mg of N were steam-distilled in a glass distillation apparatus following samples enriched with 50 atom % /sup 15/N. Twelve procedures were compared in this study, including most of those previously proposed in the literature. None of the procedures completely eliminated cross-contamination; however, some were considerably more effective than others. The results suggest that, when a glass distillation apparatus is used in /sup 15/N-tracer research, the best way to reduce cross-contamination error is to distill two aliquots of each sample whenever possible, discarding the first distillate and retaining the second for isotope-ratio analysis. When this is not possible, it is recommended that 1 mL of 1M formic acid be distilled for 1 min and 25 mL of 16.4 M (95%) ethanol be distilled for 3 min between samples. This procedure can be made more effective by increasing the amount of formic acid used and extending distillation beyond 1 min.

• Research Organization: Univ. of Illinois, Urbana
• OSTI ID: 7190787
• Journal Information: Soil Sci. Soc. Am. J.; (United States), Journal Name: Soil Sci. Soc. Am. J.; (United States) Vol. 50:1; ISSN SSSJD
• Country of Publication: United States
• Language: English

Related Subjects

510101* -- Environment
Terrestrial-- Basic Studies-- Radiometric Techniques-- (-1989)
54 ENVIRONMENTAL SCIENCES
AMMONIUM COMPOUNDS
AMMONIUM SULFATES
CHEMICAL ANALYSIS
COMPARATIVE EVALUATIONS
CONTAMINATION
DATA COVARIANCES
INHIBITION
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
MASS SPECTROSCOPY
NITROGEN 15
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
OXYGEN COMPOUNDS
QUANTITATIVE CHEMICAL ANALYSIS
SPECTROSCOPY
STABLE ISOTOPES
SULFATES
SULFUR COMPOUNDS