Tetraglyme Trap for the Determination of Volatile Organic Compounds in Urban Air. Projects for Undergraduate Analytical Chemistry

Abstract

Volatile organic compounds (VOCs), including benzene and its derivatives, contribute significantly to the pollution of urban air; at low altitudes, VOCs enhance ozone production. Monitoring VOCs in urban air has important health implications, especially since asthma and other lung diseases in inner-city communities are above the national average. Present methods for the determination of VOCs in ambient air are expensive and complex; the search is on for simpler methods. Students at Medgar Evers College use tetraglyme (tetraethylene glycol dimethyl ether) to scrub a variety of VOCs from ambient air. The chilled tetraglyme traps VOCs as the air is bubbled through it. The VOCs are then dispersed in water, from which they are analyzed by purge-and-trap, followed by GC-MSD (gas chromatography-mass selective detector). This method has been used for a number of projects for the quantitative analysis course. Students are also introduced to the practical features of 23-factorial design of experiments to optimize the method; they monitor three variables (location, volume of tetraglyme, and sampling rate) simultaneously. This method is simple, low-cost, and appropriate for undergraduate students to monitor a number of compounds in ambient and indoor air.