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    气阻稳流-阀切换除氧技术结合气相色谱法快速测定环境空气中的SF6

    Rapid Determination of Sulfur Hexafluoride in Enviornmental Air by Gas Chromatography Coupled with Valve Switching for Removing Oxygen and Air Resistance for Stabilizing Airstream

    • 摘要: 建立了气相色谱-微池电子俘获检测器(GC-μECD)快速定量分析SF6的方法。采用十通阀进样,以相同规格的5Å分子筛柱作为分离柱和分析柱,通过气阻稳流、分离柱与分析柱前端压力的匹配解决了色谱分析基线的波动;通过阀切换除氧技术提高了SF6气相色谱分析速率。结果表明,在优化的试验条件下,单个气体样品的分析时间为1.0 min,SF6的体积比在1.51×10-12~4.97×10-8L·L-1内与其峰高呈线性关系,检出限(3S/N)为1.30×10-12L·L-1,测定下限(10S/N)为4.80×10-12L·L-1。采用所建立的方法连续10次分析环境空气样品,SF6测定结果的相对标准偏差为0.61%。

       

      Abstract: A method was established to rapid quantitatively analyze SF6 by gas chromatography (GC) with micro-cell electron capture detector. A gas sample was inducted to GC by a ten-port valve. Two 5Å molecular sieve columns with same specification were used for separating and analyzing respectively. Chromatographic baseline fluctuation was eliminated by stabilizing airstream with air resistance and matching the front air pressure of separating column and analytical column. Gas chromatographic analysis rate of SF6 was improved by removing oxygen through valve switching. The results showed that, under the optimzed experimental conditions, the analysis time of a single gas sample was 1.0 min, and linear relationship was found between peak height and volume ratio of SF6 within 1.51×10-12-4.97×10-8L·L-1, with detection limit (3S/N) ) of 1.30×10-12L·L-1, and the lower limit of determination (10S/N) of 4.80×10-12L·L-1. The enviornmental air samples were analyzed 10 times by the proposed method, and the relative standard deviation of the determination results of SF6 was 0.61%.

       

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