Modified ion source triple quadrupole mass spectrometer gas chromatograph for polycyclic aromatic hydrocarbon...

Area of Science:

• Analytical Chemistry
• Environmental Science
• Mass Spectrometry

Background:

• Traditional methods struggle with comprehensive polycyclic aromatic hydrocarbon (PAH) analysis.
• Existing gas chromatography electron-impact/triple-quadrupole mass spectrometry (GC-EI/MS/MS) systems are limited in identifying and quantifying a broad range of PAHs.
• US EPA priority pollutant lists often do not cover the full spectrum of relevant PAHs.

Purpose of the Study:

• To develop and validate an advanced GC-EI/MS/MS method for the quantitative separation of 62 PAHs.
• To overcome limitations of off-the-shelf instruments for complex PAH mixtures.
• To achieve high sensitivity and accuracy in PAH determination.

Main Methods:

• Modification of GC-EI/MS/MS with a novel hydrogen-injected self-cleaning ion source and a 9mm extractor lens.
• Optimization of chromatographic conditions, including gas flow, temperature programming, and column selection.
• Utilizing multiple-reaction-monitoring (MRM) mode for sensitive and selective detection.

Main Results:

• Successful quantitative separation of 62 PAHs, including challenging isomers.
• Achieved a wide linear range (1-10,000 pg/µL) and low detection limits (<2 pg/µL).
• Demonstrated high accuracy (within 5% of true values) and excellent linearity (r² > 0.998).

Conclusions:

• The modified GC-EI/MS/MS system provides a robust and sensitive platform for comprehensive PAH analysis.
• This method significantly advances the capability for identifying and quantifying a wider array of PAHs compared to previous techniques.
• The developed approach enables accurate quantification of complex PAH mixtures, including isomers previously difficult to resolve.