@Analysis of benzene emissions in air

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.

@Applications & Benefits

1. Applications

The Benzene in Air application shows an excellent performance as demonstrated in the tables using a custom calibration gas standard.

- Detection limits of Benzene in Air.

- Repeatability of Benzene in Air

2. Benefits

- Automated analysis of Benzene & C1-C6 hydrocarbons in air in one run

- Analysis can be extended upto BTEX

- Integrated gas sampling, absorbing & desorbing

- Various options for sample collection

- Based on proven sampling technique for VOC in Air

- Up to 8 samples or standards can be selected and sampled

- Excellent performance specifications

@Configuration & Options

1. Configuration

The Benzene in Air application is based on Agilent Technologies 8890 GC

configured with:

- Flame Ionized Detector (FID) or Thermal Conductivity Detector (TCD)

- Custom programmed temperature vaporization (PTV) injector

- Analytical column and pre-column to backflush the hydrocarbon matrix

- Sampling unit including a samplingpump, a mass flow controller and 

  a multipositioning valve.

2. Options

The analysis can be extended to determine BTEX in Air. To extend the analysis to C6-C8 aromatic compounds (BTEX Analysis) just switch the backflush after elution of o-Xylene.