Abstract
Abstract. A fast two-dimensional gas chromatography (GC-MS) method that uses heart-cutting and thermal extraction (TE) and requires no chemical derivatization was developed for the determination of anhydro-sugars in fine aerosols. Evaluation of the TE-GC-GC-MS method shows high average relative accuracy (≥90%), reproducibility (≤10% relative standard deviation), detection limits of less than 3 ng/μL, and negligible carryover for levoglucosan, mannosan, and galactosan markers. TE-GC-GC-MS- and solvent extraction (SE)-GC-MS-measured levoglucosan concentrations correlate across several diverse types of biomass burning aerosols. Because the SE-GC-MS measurements were taken 8 years prior to the TE-GC-GC-MS ones, the stability of levoglucosan is established for quartz filter-collected biomass burning aerosol samples stored at ultra-low temperature (−50 °C). Levoglucosan concentrations (w/w) in aerosols collected following atmospheric dilution near open fires of varying intensity are similar to those in biomass burning aerosols produced in a laboratory enclosure. An average levoglucosan-mannosan-galactosan ratio of 15:2:1 is observed for these two aerosol sets. TE-GC-GC-MS analysis of atmospheric aerosols from the US and Africa produced levoglucosan concentrations (0.01–1.6 μg/m3) well within those reported for aerosols collected globally and examined using different analytical techniques (0.004–7.6 μg/m3). Further comparisons among techniques suggest that fast TE-GC-GC-MS is among the most sensitive, accurate, and precise methods for compound-specific quantification of anhydro-sugars. In addition, an approximately twofold increase in anhydro-sugar determination may be realized when combining TE with fast chromatography.
Highlights
Levoglucosan (LG, 1,6-anhydro-β-D-glucopyranose) is an important organic marker for biomass burning
Over a 9-hr period, replicate 1μL injections (n = 5) of the 100 ng/μL MA standards onto quartz filters resulted in a thermal extraction (TE)-gas chromatography (GC)-GC-MS method precision of 3.0–7.0% RSD
A fast two-dimensional GC-MS method with thermal extraction was developed for trace quantification of anhydro-sugars in biomass burning and atmospheric aerosols
Summary
Levoglucosan (LG, 1,6-anhydro-β-D-glucopyranose) is an important organic marker for biomass burning. Once formed as a pyrolysis product of biomass combustion, it is used as an organic marker in atmospheric modeling studies (Fraser et al, 2000; Simoneit et al, 1999a, b, 2001; Elias et al, 2001), in sediment and Antarctic ice cores for understanding the paleorecord (Gambaro et al, 2008), in liquid biofuel synthesis (Branca et al, 2003; Gravitis et al, 2004), and as a urinary biomarker for approximating animal and human exposures to biomass smoke (Migliaccio et al, 2009) For these reasons, there is high demand for quantitative analytical data for LG. We offer evidence that LG in biomass burning aerosol stored at ultra-low temperatures (−50 ◦C) is stable for nearly a decade
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