|Abstract Title:||GC Solution for the Automated Analysis of Benzene in Air|
|Session Choice:||Field Based analysis|
|Presenter Name:||Mr Harm Moes|
|Company/Organisation:||Da Vinci Laboratory Solutions|
Abstract Information :
To reduce exposure to air pollution several limits and target values for air quality have been set. The maximum value for benzene exposure is currently set at 0.7 mg/m3 (0.2 ppm). To determine Benzene in air Da Vinci Laboratory Solutions developed an automated GC solution equipped with a unique gas sampling unit that allows sampling up to 8 gaseous samples. This sampling technique has been used for the analysis of VOCâ€™s in air. GC Configuration The Benzene in Air application is based on an Agilent Technologies 7890B GC configured with a FID or TCD and a custom programmed temperature vaporization (PTV) injector. The application is equipped with an analytical column and a pre-column to backflush the hydrocarbon matrix. The sampling unit uses a sampling pump, a mass flow controller and a multi-positioning valve. The multi positioning valve allows sampling direct from a Tedlar bag or sample directly from the open-air. Up to 8 samples or standards can be automatically selected and analyzed. Automated Analysis 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. The systemâ€™s PTV injection port is modified to contain a sorbent tube as injection port liner which ensures a rapid adsorption and desorption of Benzene. Alternatively, collect the sample on a sorbent trap using a programmable sampling pump. The sorbent trap is placed in the PTV inlet and automatically purged prior to thermal desorption and subsequent analysis. The gas sampling unit automates the process of sampling, adsorbing and desorbing. After benzene has eluted from the precolumn to the polar column, the remainder of the matrix is back-flushed to vent. The Benzene in Air analysis requires 25 minutes. To extend the analysis to C6-C8 aromatic compounds (BTEX Analysis) just switch the backflush after elution of o-Xylene. Excellent Repeatability The Benzene in Air application shows an excellent performance using a custom calibration standard, which will be explained in the poster.