LAUSR

A method using ultra high performance liquid chromatography coupled to a high resolution Orbitrap mass spectrometer was developed to identify and quantify imidazoles in aqueous extracts of aerosol particles. The aqueous particle extract was used without further enrichment or sample clean-up. Five columns were tested for efficient separation of 10 imidazoles and the Acquity HSS T3 column was chosen for further optimization. Low limits of detection (<25 nM) and good intraday and interday repeatability (<1.6% and <6%, respectively) were achieved. Investigation of matrix effects showed that external calibration is applicable when the loading of organic carbon in the sample is below 10 μg m-3 . The developed method was applied to 10 real samples and 6 out of the 10 test imidazoles were successfully quantified, while 6 further imidazoles were qualitatively identified, among them 4-imidazolecarboxaldehyde and 4-methyl-5-imidazolecarboxaldehyde. Due to the minimal sample preparation approach, the short run time for each sample, and the low detection limits, the developed method shows advantages over previously published methods and enables for a fast screening of a large number of samples to quantify imidazoles in aqueous particle extracts. This article is protected by copyright. All rights reserved.