Development of a thermoelectric cold trap system for use in the analysis of trace atmospheric compounds

摘要

A prototype of a thermoelectric cold rap system has been designed, built and evaluated. The unit is used to preconcentrate trace atmospheric compounds prior to analysis. The thermoelectric cold trap unit provides an alternative to the liquid nitrogen cooled traps normally used as a measn to preconcentrate sampled components. The thermoelectric system is especially applicable in field monitoring programs, where logistical burdens are often encountered when supplying large amounts of liquid cryogens. Likewise, one does not have to be concerned with the expense and owntime associated with the use of liquid cryogens. The thermoelectric cold trap assembly can be easily interfaced with any chromatographic system using a two position six-port valve. The operating principle is pased upon the normal sample adsorption/desorption cycle and GC analysis. In this study we report on the trapping and release efficiency using low ppb levels or targeted volatile organic compounds (VOCs).