Liquid Sampling-Atmospheric Pressure Glow Discharge Ionization as a Technique for the Characterization of Salt-Containing Organic Samples
by Alves, M. R.; Sauer, J. S.; Prather, K. A.; Grassian, V. H.; Wilkins, C. L.
Typical ionization techniques used for mass spectrometry (MS) analysis face challenges when trying to analyze organic species in a high-salt environment. Here, we present results using a recently developed ionization source, liquid sampling-atmospheric pressure glow discharge (LS-APGD), for marine-relevant salt-containing organic samples. Using two representative sample types, a triglyceride mixture and dissolved organic matter, this method is compared to traditional electrospray ionization (ESI) under saline and neat conditions. LS-APGD produced equal or higher (15%+) ion intensities than those of ESI for both salt-containing and neat samples, although important differences linked with adduct formation in high-salt conditions explain the molecular species observed. For all sample types, LS-APGD observed a higher diversity of molecules under optimized settings (0.25 mm electrode spacing at 20 mA) compared to traditional ESI. Furthermore, because the LS-APGD source ionizes molecular species in a similar to 1 mm(3) volume plasma using a low-power source, there is the potential for this method to be applied in field studies, eliminating desalting procedures, which can be time-consuming and nonideal for low-concentration species.
- Journal
- Analytical Chemistry
- Volume
- 92
- Issue
- 13
- Year
- 2020
- Start Page
- 8845-8851
- URL
- https://dx.doi.org/10.1021/acs.analchem.0c00361
- ISBN/ISSN
- 1520-6882; 0003-2700
- DOI
- 10.1021/acs.analchem.0c00361