Characterisation of atmospheric organic aerosols with one- and multidimensional liquid chromatography and mass spectrometry : state of the art and future perspectives

Abstract

Aerosol particles are important components of the Earth's atmosphere and affect air quality and climate. They are small enough to penetrate deep into human lungs and are associated with serious short- and long-term health effects. However, aerosols also affect Earth's climate directly through scattering and absorption of solar radiation and indirectly through their role as cloud condensation nuclei. A large fraction (∼50 %) of the submicron aerosol mass in the troposphere consists of organic material. In recent years in particular, some progress has been made, especially in the molecular characterisation of individual target analytes and in the determination of the physicochemical properties of organic aerosol constituents. However, knowledge gaps remain, especially information on low- and semi-volatile, often highly oxidized organic compounds or highly reactive compounds. For these classes of compounds, different liquid chromatography-mass spectrometry (LC-MS) systems have become preferred analytical methods in recent years. Although these methods offer a wide range of applications, they can be limited to specific analytes. Therefore, multidimensional LC and MS methods have also been introduced in atmospheric sciences to increase either the fraction of organic mass analysed or the degree of identification of individual components. In this review article, we present the main applications of advanced one- and multidimensional LC and MS methods in the analysis of atmospheric particles in non-targeted and targeted approaches, highlight their opportunities and limitations, and outline the main challenges for future applications in atmospheric sciences.