Quantification of 21 sugars in tropospheric particulate matter by ultra-high-performance liquid chromatography tandem mass spectrometry

Abstract. Sugars compose an important class of compounds by mass in atmospheric particulate matter (PM), often with biogenic and anthropogenic sources, many of them still poorly characterized. These sugars are mainly analysed by gas-chromatography coupled to mass spectrometry (GC-MS) or ion chromatography coupled with pulsed amperometric detection (IC-PAD). However, these techniques present several disadvantages such as a complex preparation for GC-MS, or a limited range of possible analytes and elevated limits of quantification for IC-PAD. This hinders our capability to perform analyses of extensive time series, in order to develop our knowledge of the phenomenology of these species. In this paper, we present the validation of an ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous quantification of 21 sugars in atmospheric PM. The sample preparation is simple, fast and safe, consisting of an aqueous extraction. The method was validated in terms of linearity, accuracy, repeatability, reproducibility, and recovery. This technique showed excellent linearity (r2>0.99), precision (relative standard deviation RSD <25 %) and extraction yields (results between 70 % and 120 %). The suitability of the method for analyses of samples from sites with very low PM concentrations was demonstrated with samples from the High-Altitude Research Station Jungfraujoch (JFJ), Switzerland. A series of samples spanning a 6-year period is presented. Results for arabitol, levoglucosan and 2-methyl-tetrols display strong seasonality, due to seasonal variation in chemical production and boundary layer dynamics, with atmospheric convection and transport from the valleys to high altitudes mostly in summer. This simple and fast method facilitates the analysis of large sets of PM samples and sugar compounds, and opens the door to a better understanding and attribution of their sources.