Amines in air have drawn recent scrutiny due to their potential for atmospheric chemistry and importance in production of secondary aerosol. The secondary aerosol formation can take the form of salts, due to the participation of the amine in acid-base chemistry or the form of oxidized organic compounds due to atmospheric photochemistry. Amines are emitted from both natural (i.e. forests) and anthropogenic sources such as agriculture but very few studies have been performed to quantify their emissions sources. The sampling, detection, and speciation of atmospheric amines is a very difficult field due to low concentrations (part-per-billion), stickiness, and reactivity. Direct sampling chemical ionization mass spectrometers can successfully detect atmospheric amines, however they are very expensive and often cannot elucidate structural isomers. Here we discuss two methods to potentially detect atmospheric amines and developments in trying to use the methods in real sampling. The first method is an ambient ion monitor (AIM) for sampling of the amines coupled with ion chromatography (IC) for detection. The AIM method can separate and detect most of the amines with good efficiency and low detection limit, however the smallest amines (methylamine and ethylamine) can be difficult to detect in real atmospheric samples due to ammonia usually being present at a significantly larger concentration. The second method for detection is a thermal desorption gas chromatography detection. Using either a flame ionization (FID) or nitrogen phosphorous detector (NPD) allows for detection without interference from ammonia, however the detection limits for most compounds are not at the level allowing routine atmospheric sampling for amines. Figures of merit and data for both methods will be discussed and contrasted.

Detection of amines in air with ion chromatography and thermal desorption gas chromatography

2019 Spring National Meeting

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