Abstract
Abstract. An acid titration method for quantifying amine permeation rates was used to calibrate an Ambient pressure Proton transfer Mass Spectrometer (AmPMS) that monitors ambient amine compounds. The method involves capturing amines entrained in a N2 flow by bubbling it through an acidified solution (~10−5 M HCl), and the amines are quantified via changes in solution pH with time. Home-made permeation tubes had permeation rates (typically tens of pmol s−1) that depended on the type of amine and tubing and on temperature. Calibrations of AmPMS yielded sensitivities for ammonia, methylamine, dimethylamine, and trimethylamine that are close to the sensitivity assuming a gas-kinetic, ion-molecule rate coefficient. The permeation tubes were also designed to deliver a reproducible amount of amine to a flow reactor where nucleation with sulfuric acid was studied. The high proton affinity compound dimethyl sulfoxide (DMSO), linked to oceanic environments, was also studied and AmPMS is highly sensitive to it. AmPMS was deployed recently in two field campaigns and, using these sensitivities, mixing ratios for ammonia and the alkyl amines are derived from the signals. Correlations between these species and with particle formation events are discussed.
Highlights
The results of recent field campaigns show that the abundances of alkyl amines have a wide variability from site to site and temporally: they can range from single digit levels up to 100 s of pptv for some amines
Particle formation events are frequently concomitant with enhanced amine levels while some events occur at levels as low as single digit pptv, especially when sulfuric acid concentrations exceed 107 cm−3
In contrast to the other sites discussed here, the Lewes, DE, site had at times methyl and dimethylamines as the most abundant amines; this may be due to nearby poultry operations
Summary
Amines play an important role in atmospheric particle nucleation (Weber et al, 1996; Zhao et al, 2011; Ge et al, 2011; Zollner et al, 2012; Chen et al, 2012; Almeida et al, 2013; Yu et al, 2012) and they have a strong affinity for the particulate phase when it contains strong acids (Angelino et al, 2001; Barsanti et al, 2009; Bzdek et al, 2010; Smith et al, 2010) Through their effects on the abundance and properties of aerosol, amines can influence cloud condensation nuclei which has important climate implications. Recent efforts using mass spectrometry (Eisele, 1988; Sellegri et al, 2005; Hanson et al, 2011; Yu and Lee, 2012; You et al, 2014) show real time capabilities for measuring gas-phase atmospheric amines. The development of mass spectrometry techniques including AmPMS is discussed in Hanson et al (2011). These types of instruments require a continuous gas-phase source for reliable calibrations. Amine and ammonia abundances from these field studies are presented using the sensitivities determined with the permeation sources. Dimethyl sulfoxide (DMSO) has been previously detected in a marine environment with a similar mass spectrometry system (Nowak et al, 2002) and a DMSO permeation tube was constructed to calibrate a Proton Transfer Mass Spectrometer (PTrMS) (Hanson et al, 2009) and an Ambient pressure Proton transfer Mass Spectrometer. The linkage between particle formation events and gas-phase amine abundances are presented
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
