What’s In the Air We Breathe? Chemical Fingerprinting of PM2.5 by TD-GC×GC-TOF MS

Environmental Forensics
Oral (pre-recorded) Presentation

Prepared by H. Calder1, N. Watson2, J. Mayser1, H. Martin1
1 - Markes, Markes International, Gwaun Elai medi-science campus, Llantrisant, RCT, CF72 8XL, United Kingdom
2 - Markes International Inc, 2355 Gold Meadow Way, Gold River, California, 95670, United States

Contact Information: hcalder@markes.com; +441443230935


The issue of urban air quality has received increased attention in recent years due to increased awareness of the potential health risks associated with particulate matter (PM) concentrations.
Airborne particulate matter is composed of solid and/or liquid materials of various sizes, but the fine particles with diameters of <2.5 μm (so-called PM2.5) are of most concern, as long-term exposure to PM2.5 is thought to have the biggest impact on public health. In addition to health effects, small particles can grow in size to the point that they are large enough to scatter light and form “haze”.
PM2.5 consists of a wide range of components, from both primary emissions (e.g. vehicle exhausts or forest fires) and secondary reactions (i.e. compounds formed in the atmosphere by chemical reactions). It is important to have robust analysis of PM2.5 as the composition can give an indication of its source.
PM2.5 is typically trapped onto quartz fibre filters and the semi-volatile organic compounds (SVOCs) are extracted using a solvent. Direct thermal desorption (TD) of the filter avoids this time-consuming sample preparation, for simple, yet sensitive, analysis of particulate matter.
However, their identification and quantitation remains a challenge due to sample complexity. Analysts may attempt to address this using longer columns and/or slower oven temperature ramps, but this inevitably leads to longer analysis times. In recent years, the complexity of such samples has been revealed using the improved separation of comprehensive two-dimensional GC coupled with time-of-flight mass spectrometry (GC×GC–TOF MS)
Here, we demonstrate the enhanced performance of a TD-GC×GC–TOF MS through analysis of a number of real-world PM2.5 filters sampled in India.