S_2OF_(10)气体标准样品制备方法和测定方法研究

Preparation Technique of S 2OF 10 Gas Standard Sample and Determination Method of the Trace S 2OF 10 in SF\-6

提出了一系列的安全、方便、可靠、在线和可连续操作的热解吸／色谱分析柱制备 Ｓ２ Ｏ Ｆ１０纯品、指数稀释法配制 Ｓ２ Ｏ Ｆ１０标准样品、应用定量校正系数测定样品中痕量 Ｓ２ Ｏ Ｆ１０的方法和技术。分别采用气相色谱、红外光谱、气相色谱／质谱等方法对色谱制备的 Ｓ２ Ｏ Ｆ１０纯品进行了纯度分析和测定。配制 Ｓ２ Ｏ Ｆ１０标准气体的体积分数范围为 ８．０×１０－ ７～２．６×１０－ ４。气相色谱测定 Ｓ２ Ｏ Ｆ１０的定量校正系数为 ０．１９７，测定方法的相对误差范围为 １．８％～２０％ 。 Ｓ２ Ｏ Ｆ１０的吸附／热解吸回收率为 ９８．２％ ，相对标准偏差（ Ｒ Ｓ Ｄ）为 ６．２％ 。

In this paper a series of methods and techniques for the S 2OF 10 standard sample preparation and quantitative determination are presented. They are, the preparation of S 2OF 10 by preparative chromatography with adsorption/thermal desorption, the standard sample of S 2OF 10 gas prepared by exponential dilution and the gas chromatography/flame photometric detector(GC/FPD) determination of trace S 2OF 10 from an SF\-6 sample with quantitative calibration factor. Especially, the S 2OF 10 gas from a used SF\-6 sample was directly separated and concentrated through a U\|adsorbent\|tube packed with 300 mg of Porasil A in a cold trap (-63 ℃) with liquid\|nitrogen and chloroform. Then it was purified by preparative\|GC and to be injected into a preparative system of standard gas sample. In the meantime, the S 2OF 10 gas obtained was confirmed by the methods of GC/FPD, infrared spectrophotometer(IR) and gas chromatography/mass spectrometer(GC/MS) separately. The sub\|ppm(by volume) level of the S 2OF 10 and SF\-6 mixture samples were prepared by use of the exponential dilution system. The GC/FPD experimental results showed that the detection linear range of S 2OF 10 gas concentration was 0.80×10 -6 \|2.60×10 -4 (volume fraction) and the quantitative calibration factor of the S 2OF 10 was 0.197 based on SF\-6. The determination errors of quantitative calibration factor were 1.8%\|20% and S 2OF 10 recovery of the adsorption/thermal desorption was 98.2% (n=9) and its relative standard deviation was 6.2%. In addition, the results also showed that it is a simple and rapid method with good linearity and reproducibility.