Vanillic acid in polar ice cores

This discussion paper is/has been under review for the journal Climate of the Past (CP). Please refer to the corresponding final paper in CP if available. Abstract Biomass burning generates a wide range of organic compounds that are transported via aerosols to the polar ice sheets. Vanillic acid is a product of conifer lignin combustion , which has previously been observed in laboratory and ambient biomass burning aerosols. In this study a method was developed for analysis of vanillic acid in melted 5 polar ice core samples. Vanillic acid was chromatographically separated using reversed phase LC and detected using electrospray triple quadrupole mass spectrometry (ESI-MS/MS). Using a 100 µL injection loop and analysis time of 4 min, we obtained a detection limit (S : N = 2) of 58 ppt (parts per trillion by mass) and an analytical precision of ±10 %. Measurements of vanillic acid in Arctic ice core samples from the Siberian 10 Akademii Nauk core are shown as an example application of the method.