A two-column method for long-term monitoring of non-methane hydrocarbons (NMHCs) and oxygenated volatile organic compounds (o-VOCs)

A method has been developed for Concurrent analysis of C-2-C-(7) hydrocarbons and C-2-C-5 oxygenated volatile organic compounds (o-VOCs) including alcohols, aldehydes. ketones and ethers. A multi-bed. Peltier-cooled adsorbent trap. consisting of Carboxen 1000 and Carbopack B. was used to acquire one Sample per hour. Upon injection the sample was split in an approximately 50:50 ratio between a 50 m aluminum oxide (Al2O3) porous layer open tubular (PLOT) Column and a 10 m LOWOX column. Eluents from each column were then analysed using flame ionisation detection (FID). Regular calibration of the system was performed using a standard cylinder mixture at the parts per billion by volume (ppbV) level for non-methane hydrocarbons (NMHCs) and a permeation tube method for the oxygenated species. The system is fully automated with NMHC detection limits between I and 10 parts per trillion by volume (pptV) and o-VOC detection limits between 10 and 40 pptV.