New sensitive and quantitative analysis method for organic nitrogen compounds in urban aerosol samples

Area of Science:

• Environmental Chemistry
• Analytical Chemistry

Background:

• Atmospheric aerosols are complex mixtures, but organic nitrogen (ON) components are poorly understood.
• Existing methods for ON speciation lack sensitivity and quantitative accuracy.

Purpose of the Study:

• To develop and validate a sensitive and quantitative method for speciating organic nitrogen in ambient atmospheric aerosols.
• To identify and quantify various ON compounds in urban aerosol samples.

Main Methods:

• Aerosol samples were extracted and analyzed using comprehensive two-dimensional gas chromatography with a nitrogen chemiluminescence detection system (GCxGC-NCD).
• The GCxGC-NCD method was optimized for selectivity, sensitivity, and equimolar response to ON compounds.
• Limits of detection (LOD) and quantitation (LOQ) were determined for ON standards.

Main Results:

• The GCxGC-NCD method demonstrated high selectivity and sensitivity for ON speciation.
• Between 21 and 57 different ON compounds were detected in urban aerosol samples.
• Pyrrole and N-butyl-benzenesulfonamide were identified as the most abundant ON compounds, with an average total identified ON mass loading of 532.51 ngON m⁻³.

Conclusions:

• The developed GCxGC-NCD method provides a significant advancement for the sensitive and quantitative analysis of organic nitrogen in atmospheric aerosols.
• This method facilitates a better understanding of the composition and sources of organic nitrogen in the atmosphere.