Real-Time Quantitative Analysis of Combustion-Generated Polycyclic Aromatic Hydrocarbons by Resonance-Enhanced...

Area of Science:

• Analytical Chemistry
• Combustion Science
• Physical Chemistry

Background:

• Polycyclic aromatic hydrocarbons (PAHs) are significant combustion byproducts.
• Accurate measurement of PAHs in flames is crucial for understanding combustion processes and emissions.

Purpose of the Study:

• To develop and apply a method for real-time quantification of specific PAHs in a methane diffusion flame.
• To determine the concentrations of naphthalene, fluorene, and anthracene using advanced spectroscopic techniques.

Main Methods:

• Combined resonance-enhanced multiphoton ionization (REMPI) time-of-flight mass spectrometry with on-line flame sampling.
• Utilized one-color REMPI for naphthalene and fluorene, and two-color REMPI for anthracene detection.
• Employed gas-phase standard additions for real-time absolute concentration calibration.

Main Results:

• Measured naphthalene concentrations from 100 ppbV to 6 ppmV.
• Quantified fluorene concentrations below 50 ppbV.
• Determined anthracene concentrations in the 5-40 ppbV range.
• Demonstrated isomer-selective detection of larger PAHs like perylene and benzo[a]pyrene.

Conclusions:

• The developed REMPI-MS method provides accurate, real-time quantification of PAHs in flames.
• This technique is valuable for studying PAH formation and speciation in combustion environments.
• The method shows potential for detecting a wide range of PAHs, including larger, more complex molecules.