title: A cryogen-free refrigerating preconcentration device for the measurement of C2 to C4 hydrocarbons in ambient air.
abstract: A cryogen-free refrigerating preconcentration device for the enrichment of trace amounts of highly volatile organic compounds in the atmosphere prior to analysis has been designed and evaluated. The device consists of a microtrap housed in an insulated box, which is cooled by a conventional refrigeration unit. Experimental parameters, including adsorbent mass, trapping temperature, and thermal desorption temperature, were optimized. The on-line coupling of the device to a GC allows sufficient enrichment and separation of C2 to C4 hydrocarbons in less than 40 min without a second cryotrap. The target compounds analysis showed good linearity (correlation coefficients >0.99) and repeatability (relative standard deviation <5%). Detection limits for the 10 volatile organic compounds ranged from 14 ppt to 52 ppt, under the conditions of a 500 mL sampling volume and -10 °C trapping temperature. Real air sample measurements were conducted at an urban site, and five VOCs including ethane, ethene, propane, propene and 1-butene were detected and quantified.
authors.affiliation: Department of Instrumentation & Analytical Chemistry, Key Lab of Separation Science for Analytical Chemistry of CAS, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Peng
authors.forename: Jianwei
authors.initials: J
authors.lastname: Wang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Shen
authors.forename: Dapeng
authors.initials: D
authors.lastname: Wu
authors.forename: Yafeng
authors.initials: Y
authors.lastname: Guan