A dual-channel gas chromatography method for the quantitation of low and high concentrations of NF₃ and CF₄ to study membrane separation of the two compounds

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• 作者：D.J. Branken ; J.P. le Roux ; H.M. Krieg ; G. Lachmann
• 关键词：NF3 quantitation ; CF4 quantitation ; Separation of NF3 and CF4 ; Pulsed discharge helium ionization ; Super Q
• 刊名：Journal of Chromatography A
• 出版年：2013
• 出版时间：13 September, 2013
• 年：2013
• 卷：1307
• 期：Complete
• 页码：180-190
• 全文大小：660 K

文摘

A dual-channel gas chromatographic method is described in this paper that can be conveniently used for quantitation of NF₃/CF₄ mixtures with a thermal conductivity detector (TCD) on one channel for the quantitation of high-concentrations, and a pulsed discharge helium ionization detector (PDHID) on a second channel for the quantitation of low concentrations. It is shown that adequate separation is achieved on both channels with this dual single-column setup in which column switching as used for NF₃/CF₄ analysis in industrial chromatographic methods are not required, thus yielding an effective analysis method for laboratory-scale investigations. In addition, the use of packed columns with purified divinylbenzene-styrene co-polymers as the sole stationary phase yields satisfactory resolution between NF₃ and CF₄ at isothermal conditions of 30 ¡ãC, with elution times of less than 8 min on the TCD channel and less than 4 min on the PDHID channel. Consequently, this method allows for reliable, straight-forward quantitation of NF₃/CF₄ mixtures, which is necessary when studying the commercially important problem of NF₃ and CF₄ separation by different methods. Therefore, the applicability of the method to studying membrane separation of NF₃ and CF₄ is briefly discussed and illustrated, for which the dual-channel setup is especially beneficial.