The Benzene in Air application is based on an Agilent Technologies Gas Chromatograph configured with a sampling unit that uses a pump, a mass flow controller and a multi-positioning valve to collect samples from e.g. a Tedlar bag or to takie a sample directly from the outside air. 

Collect the samples in Tedlar bags and use the stream selection valve to select either standards, samples and/or multiple samples for an automated analysis. An injection port is modified to contain a sorbent tube as an injection port liner to ensures a rapid absorption and desorption of Benzene.

Alternatively collect the sample on a sorbent trap using a programmable sampling pump. The sorbent trap is placed in the inlet and automatically purged prior to thermal desorption and subsequent analysis. This proven sampling technique has already been used for the analysis of VOC in air.

Up to eight samples or standards can be automatically selected and sampled. The gas sampling unit automates the process of sampling, absorbing and desorbing. After benzene has eluted from the precolumn to the polar column, the remainder of the matrix is backflushed to vent. 

Based on this configuration the GC application determines the Benzene emissions and C1-C6 hydrocarbons in air samples in one consecutive run.