In-situ measurement of methyl bromide in indoor air using long-path FTIR spectroscopy

摘要

A new Fourier transform infrared (FTIR) spectrometer has been set up at the California Department of Flood and Agriculture for monitoring gas phase pesticides and inert ingredients used in the formulation of pesticides. To allow detection of trace quantities down to the ppm range, the FTIR instrument has been interfaced to a custom, external open multiple reflection system with a base pathlength of 2.5 m. The mirror system is of the double corner cube White type design capable of achieving a total absorption pathlength of 140 m. Our initial application was to monitor the concentration of methyl bromide after controlled releases of this fumigant into an indoor environment.