The Laminar Flow Torch for Gas Chromatographic He Microwave Plasma Detection of Pyrethroids and Dioxins

Abstract

A new laminar flow, microwave-induced plasma torch has been evaluated for its use in gas chromatography. Data were collected through a computer-controlled background-correcting polychromator system. A 0.5-mm-i.d. open quartz tube, the tangential flow torch, and the laminar flow torch were used for discharge containment and were compared. The chromatographic and spectroscopic data were used to determine the partial empirical formulas of pyrethroids and dioxins. The laminar flow torch showed improvements over both the 0.5-mm open tube and the tangential flow torch. The typical errors from the true empirical formulas were less than 4%. Detection limits were between 8 and 60 pg/s for carbon, hydrogen, bromine, chlorine, and fluorine emission signals. The compound detection limits on the carbon channel averaged 0.043 μg/mL for pyrethroids and 0.010 μg/mL for dioxins.