Session: Advances in Mass Spectrometry:

Fire smoke consists of a complex mixture of gases and particulate matter (PM). As more evidence links the PM exposure to health impacts, there is a more urgent need to develop effective methods to analyze the toxicants in the PM. Carboxylic acids (CA) and sugars including levoglucosan are polar organic compounds existing in the PM. Levoglucosan is mainly formed from cellulose combustion and can be used as a tracer of biomass burning emissions. CA may irritate the eyes, nose, and skin and cause asthma and even lung damage. However, The data about their levels in the PM is still very limited. This study aims to develop novel methods for determining levoglucosan and CA in the PM of smoke.
PM samples were collected on the quartz fiber filters using a high volume air sampling pump from the smoke of controlled fires and the wildland fires in southern California during the wildfire season in fall 2020. Gas chromatography-mass spectrometry (GC-MS) and direct analysis in real-time mass spectrometry (DART-MS) methods were developed for CA and levoglucosan analysis. For GC/MS method, CA and levoglucosan on the filter were extracted by the methanol-dichloromethane mix. The extracts were then dried under nitrogen gas, followed by the derivatization with BSTFA+TMCs 1%. The silyl derivatives were analyzed by GC-MS. For DART-MS, the precut filter samples were placed on the thermal desorption device in which the desorbed analytes were ionized by the metastable helium in the gas stream of the DART ion source and analyzed by the mass spectrometer.
Levoglucosan and selected CA in the PM were successfully detected. Both methods will be validated using the certified PM samples. The DART-MS method does not require the time-consuming solvent extraction and analyte derivatization and shows promising potential for the fast PM analysis of CA and levoglucosan in toxicant exposure studies.

Shruthi Perna

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