Automated Measurement of Particle-Phase Organic Compounds Using Chip-Scale Gas Chromatography
VIKAS GOEL, Nipun Thamatam, Nathan Kreisberg, Zinoy Manappadan, Jyothi Chintalapalli, Suman Dewanjee, John Michalek, Chien Nguyen, Masoud Agah, Gabriel Isaacman-VanWertz, Virginia Tech
Abstract Number: 596
Working Group: Instrumentation and Methods
Abstract
The atmosphere is a complex mixture of hundreds to thousands of chemical compounds, which are either directly emitted from sources or formed through atmospheric processes. Accurate detection and quantification of these compounds are critical for understanding their impacts on climate and human health. Field-deployable gas chromatography (GC) systems have significantly advanced our ability to perform near-real-time, chemically resolved measurements of gases and particles in ambient environments. However, most existing systems rely on conventional GC components that are bulky and challenging to transport. Although recent advancements have improved the portability of instruments measuring volatile gases, a truly portable system for detailed characterization of particle-phase organic compounds remains unavailable. To address this gap, we have developed a miniaturized instrument for near real-time detection of particle-phase organics. Particles are impacted into a metal temperature-controlled cell coupled with chip-scale (i.e., Microelectromechanical Systems or MEMS) components including an adsorbent trap, gas chromatography column, and photoionization detector (PID). MEMS modules are connected without adhesives using a novel Fluidic and Electrical Modular Interfacing (FEMI) architecture. The entire system, including valves, heaters, fans, pump, and mass flow controllers is controlled by an Electronic Control Unit (ECU), enabling fully automated operation. Injections of hydrocarbon standards at the same concentration produced highly consistent results with minimal standard deviation and a highly linear response (R²=0.95). The system has also been demonstrated for the collection and quantitative analysis of laboratory-generated aerosol particles through comparison to samples collected in parallel for analysis on a separate GC system. In this work we will describe the instrument, present validation, and evaluation data, and demonstrate its application to real-world ambient aerosols.