Detection of atmospheric gaseous amines and amides by a high-resolution time-of-flight chemical ionization mass spectrometer with protonated ethanol reagent ions

Abstract

Abstract. Amines and amides are important atmospheric organic-nitrogen compounds but high time resolution, highly sensitive, and simultaneous ambient measurements of these species are rather sparse. Here, we present the development of a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) method, utilizing protonated ethanol as reagent ions to simultaneously detect atmospheric gaseous amines (C1 to C6) and amides (C1 to C6). This method possesses sensitivities of 5.6–19.4 Hz pptv−1 for amines and 3.8–38.0 Hz pptv−1 for amides under total reagent ion signals of ∼ 0.32 MHz. Meanwhile, the detection limits were 0.10–0.50 pptv for amines and 0.29–1.95 pptv for amides at 3σ of the background signal for a 1 min integration time. Controlled characterization in the laboratory indicates that relative humidity has significant influences on the detection of amines and amides, whereas the presence of organics has no obvious effects. Ambient measurements of amines and amides utilizing this method were conducted from 25 July to 25 August 2015 in urban Shanghai, China. While the concentrations of amines ranged from a few parts per trillion by volume to hundreds of parts per trillion by volume, concentrations of amides varied from tens of parts per trillion by volume to a few parts per billion by volume. Among the C1- to C6-amines, the C2-amines were the dominant species with concentrations up to 130 pptv. For amides, the C3-amides (up to 8.7 ppb) were the most abundant species. The diurnal and backward trajectory analysis profiles of amides suggest that in addition to the secondary formation of amides in the atmosphere, industrial emissions could be important sources of amides in urban Shanghai. During the campaign, photo-oxidation of amines and amides might be a main loss pathway for them in daytime, and wet deposition was also an important sink.

New particle formation in the sulfuric acid–dimethylamine–water system: reevaluation of CLOUD chamber measurements and comparison to an aerosol nucleation and growth model

“…1 × 10 6 to 3 × 10 7 cm −3 , which fall into the range for most observations of atmospheric boundary layer NPF events (e.g., Kulmala et al, 2013). The DMA mixing ratio for most of the data shown in this study is ∼ 40 pptv (1 × 10 9 cm −3 ), which is within the rather wide range of observations (0.1 to 157 pptv, i.e., 2.5 × 10 6 to 4 × 10 9 cm −3 ) for C2-amines to which DMA belongs (Yao et al, 2016).…”

“…Despite the strong evidence that sulfuric acid-amine nucleation is very efficient, it has rarely been observed in the atmosphere. Only one study has so far reported sulfuric acid-amine nucleation (Zhao et al, 2011) despite amine mixing ratios of up to tens of parts per trillion volume at some sites (Yu and Lee, 2012;You et al, 2014;Freshour et al, 2014;Yao et al, 2016). A global modeling study of sulfuric acid-amine nucleation has been carried out so far (Bergman et al, 2015), applying a nucleation parametrization based on the measurements of Almeida et al (2013) and Glasoe et al (2015).…”

New Particle Formation in the Atmosphere: From Molecular Clusters to Global Climate

“…Hanson et al () and Zheng et al () have used protonated water ions as reagent to measure various amines and ammonia. H. Yu and Lee () applied protonated ethanol and acetone ions as reagent to detect amines and ammonia together, and this ion‐molecule reaction scheme later was applied for amine measurements also by other groups (Yao et al, ; Yao et al, ). Either quadrupole mass spectrometry or high‐resolution time of flight mass spectrometer (HR‐TOF‐MS) has been used as detector.…”

Particle acidity and sulfate production during severe haze events in China cannot be reliably inferred by assuming a mixture of inorganic salts

“…Such a correlation was also reported by other researchers Yu et al, 2005), suggesting the co-occurrence and internally mixing state of both compounds in the atmosphere. In addition, the previous field measurements also revealed that WSOM in China is not only enriched in carboxylic acids (including oxalic acid) but also in other organic species, including carbonyls, amines, and water-soluble nitrogen-containing organic compounds (G. Wang et al, 2010;Wang et al, 2013;Zheng et al, 2015;Yao et al, 2016;F. Liu et al, 2017).…”

“…Also, organic acids engage in particle-phase reactions with the basic species (i.e., NH 3 and amines), significantly enhancing the particle hygroscopicity and reducing the acidity (GomezHernandez et al, 2016). In addition, because of their strong basicity and high abundance, amines likely play a key role in reducing the particle acidity in China (L. Wang et al, 2010a, b;Qiu et al, 2011;Qiu and Zhang, 2012;Dong et al, 2013;Zheng et al, 2015;Yao et al, 2016;F. Liu et al, 2017).…”