Esterification of Carboxylic Acids Present on Airborne Particulate Matter During Methanol Extraction and Storage

Abstract

Concentrated methanol extracts of airborne particulate matter (APM) collected on glass fiber filters were examined by gas chromatography to document sample composition changes during storage. A major component of the chromatographic profile was observed to decrease in abundance with time while another compound was increasing. These compounds were identified by Gas Chromatography-Mass Spectrometry as myristic acid and methyl myristate, respectively. Although methanol is a common extracting solvent for these samples, this is the first study to document the in-situ esterification of acids from APM during storage of the methanol extracts.

Key Words:

• Air particulates
• sample storage
• esterification
• methanol extraction.