A two-dimensional gas chromatographic method (GC-GC) is described for the analysis of trace benzene in styrene. This method uses the Agilent 6890N GC system equipped with a Deans switch device. The method can be used in a prefractionator mode to analyze trace benzene in styrene according to the proposed ASTM method [1]. It can also be used in a heart-cutting mode to transfer more precisely just the benzene peak from the primary column to the sec- ondary column. The Agilent 6890N electronic pneumatics control and flow calculation software are used for setting up the precise flows and pressures required. Excellent calibration and sensitivity of this system is demonstrated in both prefractionator mode and heart-cutting mode, and the interference can be greatly reduced by the heart-cutting.
The document details a method for analyzing trace benzene in styrene using the Agilent 6890N GC system equipped with a Deans switch device. The method can be operated in two modes: prefractionator mode to analyze trace benzene according to the proposed ASTM method, and heart-cutting mode to transfer the benzene peak more precisely from the primary column to the secondary column. This approach reduces interference from other hydrocarbons.
| Primary column | HP-1 15 m, 0.53 mm, 3.0 ym |
|---|---|
| Secondary column | INNOWax 60 m, 0.53 mm, 1.0 um |
| Data system | Agilent multitechnique ChemStation rev. A.08.01 |
The calibration range covers benzene concentrations from 1 ppm to 1000 ppm.
The Deans Switch Calculator is used to determine the correct column flows, inlet pressure, PCM pressure, and restrictor size.