Luan Tian, Fang Shuang-xi, Zhou Ling-xi, Wang Hong-yang, Zhang Gen
Huan Jing Ke Xue. 2015 Jan;36(1):34-9.
A high precision GC system with a pulsed discharge helium ionization detector was set up based on the commercial Agilent 7890A gas chromatography. The gas is identified by retention time and the concentration is calculated through the peak height. Detection limit of the system is about 1 x 10(-9) (mole fraction, the same as below). The standard deviation of 140 continuous injections with a standard cylinder( concentration is roughly 600 x 10(-9)) is better than 0.3 x 10(-9). Between 409.30 x 10(-9) and 867.74 x 10(-9) molecular hydrogen mole fractions and peak height have good linear response. By using two standards to quantify the air sample, the precision meets the background molecular hydrogen compatibility goal within the World Meteorological Organization/Global Atmosphere Watch (WMO/GAW) program. Atmospheric molecular hydrogen concentration at Guangzhou urban area was preliminarily measured by this method from January to November 2013. The results show that the atmospheric molecular hydrogen mole fraction varies from 450 x 10(-9) to 700 x 10(-9) during the observation period, with the lowest value at 14:00 (Beijing time, the same as below) and the peak value at 20:00. The seasonal variation of atmospheric hydrogen at Guangzhou area was similar with that of the same latitude stations in northern hemisphere.
基于商用安捷伦7890A气相色谱仪建立了配备脉冲放电氦离子化检测器的高精度气相色谱系统。通过保留时间对气体进行识别，并通过峰高计算浓度。该系统的检测限约为1×10⁻⁹（摩尔分数，下同）。用标准气瓶（浓度约为600×10⁻⁹）进行140次连续进样的标准偏差优于0.3×10⁻⁹。在409.30×10⁻⁹至867.74×10⁻⁹的分子氢摩尔分数范围内，峰高具有良好的线性响应。通过使用两种标准对空气样品进行定量，精度符合世界气象组织/全球大气观测（WMO/GAW）计划内的背景分子氢兼容性目标。利用该方法于2013年1月至11月对广州城区大气分子氢浓度进行了初步测量。结果表明，观测期间大气分子氢摩尔分数在450×10⁻⁹至700×10⁻⁹之间变化，最低值出现在14:00（北京时间，下同），峰值出现在20:00。广州地区大气氢的季节变化与北半球同纬度站点相似。
