Articles | Volume 9, issue 5
Research article
13 May 2016
Research article |  | 13 May 2016

Detection of dimethylamine in the low pptv range using nitrate chemical ionization atmospheric pressure interface time-of-flight (CI-APi-TOF) mass spectrometry

Mario Simon, Martin Heinritzi, Stephan Herzog, Markus Leiminger, Federico Bianchi, Arnaud Praplan, Josef Dommen, Joachim Curtius, and Andreas Kürten

Abstract. Amines are potentially important for atmospheric new particle formation, but their concentrations are usually low with typical mixing ratios in the pptv range or even smaller. Therefore, the demand for highly sensitive gas-phase amine measurements has emerged in the last several years. Nitrate chemical ionization mass spectrometry (CIMS) is routinely used for the measurement of gas-phase sulfuric acid in the sub-pptv range. Furthermore, extremely low volatile organic compounds (ELVOCs) can be detected with a nitrate CIMS. In this study we demonstrate that a nitrate CIMS can also be used for the sensitive measurement of dimethylamine (DMA, (CH3)2NH) using the NO3•(HNO3)1 − 2• (DMA) cluster ion signal. Calibration measurements were made at the CLOUD chamber during two different measurement campaigns. Good linearity between 0 and  ∼  120 pptv of DMA as well as a sub-pptv detection limit of 0.7 pptv for a 10 min integration time are demonstrated at 278 K and 38 % RH.

Short summary
This study demonstrate the detection of dimethylamine at low mixing ratios by nitrate chemical ionization mass spectrometry (CIMS). Due to simultaneously high-sensitive gas-phase measurements of DMA, sulfuric acid, and extremely low volatile organic compounds (ELVOCs), this technique can be used as a versatile tool for studying new particle formation in the atmosphere.