Size-exclusion chromatography with organic carbon detection using a mass spectrometer

Area of Science:

• Analytical Chemistry
• Environmental Science
• Organic Chemistry

Background:

• Conventional organic carbon detection methods in size-exclusion chromatography (SEC) can have limitations in sensitivity and signal quality.
• Previous systems often relied on Fourier transform infrared (FTIR) spectroscopy for detection, which may not provide optimal performance for all applications.
• Analyzing natural organic matter (NOM) requires sensitive and reliable detection techniques to understand its composition and behavior.

Purpose of the Study:

• To develop and describe a novel organic carbon detector for SEC utilizing mass spectrometry.
• To compare the performance of the new mass spectrometer-based detector with a previously established FTIR detector.
• To explore the potential for advanced characterization of NOM using this new detection system.

Main Methods:

• The novel detector employs UV-persulfate oxidation to convert organic carbon to carbon dioxide (CO2).
• Carbon dioxide is then detected using a mass spectrometer, offering high sensitivity.
• The system was evaluated for its limits of detection (LOD) and quantification (LOQ) and signal-to-noise ratio.

Main Results:

• The mass spectrometer-based detector demonstrated lower LOD and LOQ compared to an FTIR detector when calibrated with phthalate standards.
• Analysis of natural organic matter (NOM) in water yielded a superior signal-to-noise ratio with the mass spectrometer system.
• The new system successfully detected organic carbon as CO2, paving the way for further analysis.

Conclusions:

• A mass spectrometer-based organic carbon detector for SEC offers improved sensitivity and signal quality over FTIR detectors.
• This novel instrument is effective for analyzing organic carbon, including NOM, in aqueous samples.
• The use of mass spectrometry opens possibilities for stable carbon isotope ratio analysis of size-fractionated organic carbon.