10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
A Quantitative Method to Measure and Speciate Amines in Ambient Aerosol Samples
AMY P. SULLIVAN, Katherine Benedict, Jeffrey Collett, Colorado State University
Abstract Number: 252 Working Group: Instrumentation
Abstract Ambient reactive nitrogen is a mix of organic compounds that contain nitrogen and inorganic compounds like nitric acid, nitrate, ammonia, and ammonium. These various forms of nitrogen are found in both the aerosol and gas phases and in oxidized and reduced forms. The aerosol-phase reduced nitrogen is predominately thought to include ammonium and amines. In ambient samples the ammonium concentration is often routinely determined, but the contribution of amines is not. This has left limited information on the abundance and speciation of amines. In addition, in the traditional cation separation methods currently used to measure ammonium and other common inorganic ions there is significant overlap with amines that is not accounted for. Therefore, we have developed a method to discretely measure amines from ambient aerosol samples. It employs ion chromatography using a Dionex CS-19 column with conductivity detection and a methanesulfonic acid eluent gradient separation. This method allows for quantification of 16 different amines, including the series of methylamines and ethylamines as well as the different isomers of butylamine, along with the common inorganic cations. Here we will present the details of the method. We will assess the impact of the presence of amines on the determination of the common inorganic ions. We will also examine data from the analysis of ambient filter samples collected in Rocky Mountain National Park and from biomass burning source testing using this method. Even in the typical background conditions encountered in Rocky Mountain National Park, from analysis of daily low flowrate samples we were able to regularly measure almost all of the various quantifiable amines this technique can identify. The sum of the amines was generally about 0.02 µg/m3. It increased to 0.04 µg/m3 when the site was being impacted by biomass burning, largely due to observable increases in methylamine and dimethylamine.