Applications of Desorption Corona Beam Ionization-Mass Spectrometry

Importance of the Topic

Desorption corona beam ionization (DCBI) represents a cutting-edge ambient ionization technique in mass spectrometry, offering rapid analysis with minimal sample preparation. Its ability to ionize compounds across a wide polarity range under atmospheric conditions makes it highly attractive for high-throughput workflows in environmental monitoring, food safety testing, pharmaceutical screening and on-site quality control.

Goals and Study Overview

This work evaluated the performance of DCBI coupled to a quadrupole mass spectrometer (Shimadzu LCMS-2020) for direct analysis of diverse analytes. Target compounds included low-polarity hydrocarbons, medium-polarity polyaromatic hydrocarbons, polar pesticides and biological molecules, demonstrating the method’s versatility and speed.

Methodology and Instrumentation

• Sample Preparation: Standards of melamine, saturated hydrocarbons, polyaromatic hydrocarbons, testosterone, pirimicarb and methomyl dissolved in methanol or acetonitrile.
• DCBI Setup: Helium discharge gas heated to 350 °C and delivered at 0.6 L/min through a hollow-needle/ring electrode to generate a visible corona beam focused onto the sample.
• Instrument: Shimadzu LCMS-2020 quadrupole mass spectrometer with DCBI probe, controlled via LabSolutions LCMS software.
• Analytical Conditions: Positive-ion mode; high-voltage discharge +2.0 to +3.0 kV; DL temp. 250 °C; block heater 400 °C; mass range m/z 100–500; sample volume 1–2 µL.

Main Results and Discussion

All analytes produced strong protonated molecular ions regardless of polarity. Saturated and polyaromatic hydrocarbons yielded clean homologous series peaks (e.g., C10–C25 alkanes; naphthalene to chrysene in PAHs). Testosterone and melamine were detected at expected m/z values with minimal fragmentation. Pesticides pirimicarb and methomyl delivered both parent ions and characteristic fragments (e.g., methomyl fragment at m/z 106), enabling confirmatory identification. Each analysis completed in under one minute, illustrating true high-throughput capability.

Benefits and Practical Applications

• Ultra-fast analysis without chromatographic separation.
• Minimal or no sample preparation reduces labor and consumable costs.
• Broad chemical coverage from nonpolar to highly polar analytes.
• High data reproducibility due to localized corona beam sampling.
• Ideal for rapid screening in QA/QC, forensic, environmental and clinical labs.

Future Trends and Applications

Integration of DCBI with high-resolution Orbitrap or time-of-flight analyzers could enhance mass accuracy and enable structural elucidation. Automation of sample introduction and multiplexed sampling formats (e.g., microarrays or imaging stages) will expand throughput. Coupling DCBI with machine-learning algorithms for spectral interpretation promises rapid unknown identification in complex matrices.

Conclusion

The DCBI-MS platform demonstrated efficient desorption and ionization of compounds spanning wide polarity, generating reproducible protonated ions and diagnostic fragments within seconds. Its simplicity and speed position it as a valuable tool for diverse analytical applications demanding rapid qualitative screening.

References

1. Monge ME, Harris GA, Dwivedi P, Fernández FM. Chemical Reviews. 2013;113(3):2269–2308.
2. Hua W, Nefliu M, Quirke JME, Evans-Nguyen J, Kelvin S, Chen H. Analyst. 2010;135(3):688–695.