ConFlo III - an interface for high precision delta(13)C and delta(15)N analysis with an extended dynamic range

Area of Science:

• Analytical Chemistry
• Geochemistry
• Environmental Science

Background:

• Isotope ratio mass spectrometry (IRMS) is crucial for tracing elemental pathways.
• Traditional IRMS has limitations in dynamic range for delta(13)C and delta(15)N analysis.
• Elemental analyzers (EA) coupled with IRMS offer enhanced analytical capabilities.

Purpose of the Study:

• To develop and evaluate a novel interface coupling a CHN elemental analyzer (EA) to an isotope ratio mass spectrometer (IRMS).
• To extend the dynamic range of delta(13)C and delta(15)N analysis beyond two orders of magnitude.
• To achieve high precision isotope measurements across a wide range of carbon sample sizes.

Main Methods:

• Coupling of a CHN combustion device (elemental analyzer) to an isotope ratio mass spectrometer.
• Utilizing a helium dilution system for larger sample amounts to maintain isotopic integrity.
• Analysis of atropine as a model compound for carbon isotope ratio measurements.

Main Results:

• The developed interface successfully extends the dynamic range of delta(13)C and delta(15)N analysis to over three orders of magnitude.
• Precise carbon isotope ratio measurements were achieved for sample sizes ranging from 1 µg to 5 mg C.
• Blank signal correction is critical for samples < 4 µg C; precision ranged from 0.6 to 0.06 per thousand.
• Helium dilution for larger samples operated with negligible isotope fractionation.

Conclusions:

• The novel EA-IRMS interface significantly enhances the capability for high-precision, wide-range stable isotope analysis.
• The system is suitable for analyzing diverse sample sizes, from micrograms to milligrams.
• This advancement is valuable for applications requiring accurate isotopic characterization across broad concentration ranges.