High Sensitivity Analysis of Dioxins By Using a Multi Dimensional GC System (MDS-6890 Solvent-Cut System) with a Large Volume Injector
Recently, dioxin is being analyzed in a wide variety of materials. In addition to conventional environmental samples such as fly ash and exhaust gas, biological and water samples such as blood, breast milk, and tap water are being analyzed. Because the dioxin concentrations in these samples are extremely low, ultra high sensitivity is one of the critical features required for analytical systems. Higher sensitivity in analysis is obtained by improving the performance of the mass spectrometer as well as improving the injection techniques for the gas chromatograph. The PTV (Programmable Temperature Vaporizer) inlet is an example of such injection techniques. The PTV inlet selectively eliminates solvents at the sample injector, allows for large volume sample injection, and concentrates the compounds of interest onto the GC column.(1) However, the PTV inlet does not support solvents whose boiling point is higher than that of toluene because it is designed to separate solvents from compounds in question by controlling the injector temperature alone. Also, contamination builds up rapidly inside the injector. To address these problems, we investigated the analysis of dioxins by using a multi-dimensional gas chromatograph (MD-GC) with a large-volume injector as a high-sensitivity analytical method for dioxins.
The MD-GC connects two or more columns in series, providing an enhancement over a single column separation. It combines different types of columns to maximize the selection power and sample load, optimizing at high speed the analytical conditions for samples with a wideranging concentration level.(2)