2007 Volume 56 Issue 9 Pages 729-735
An atomic emission detector (AED) using a helium radio-frequency plasma (RFP) for gas chromatography (GC), equipped with a coaxial micro plasma torch, was developed. The torch was made by arranging two platinum tubular electrodes (1.0 mm o.d. and 0.5 mm o.d.) coaxially. The head of an optical fiber was placed on the torch, and the end was connected to a compact CCD spectrometer. The developed AED was set on a conventional GC for the measurement. When thioanisole was used as a sulfur compound, the detection limit of sulfur was obtained to be 59 pg/s (S/N = 3) at a detection wavelength of 921.3 nm with an applied power of 3 W and a flow rate of make-up gas of 1 mL/min. In the case of triethyl phosphate as a phosphorus compound, when the detection wavelength, the applied power and the flow rate of make-up gas were set at 253.4 nm, 3 W and 17 mL/min, respectively, 62 pg/s (S/N = 3) was found to be the detection limit for phosphorus. These results indicated that the applied power and/or the flow rate of plasma gas required for the developed AED for the high-sensitive detection were less than one order of magnitude smaller than that of previous reported helium RFP-AEDs.
