Simultaneous detection of 14NO and 15NO using Faraday modulation spectroscopy
Simultaneous detection of 14NO and 15NO using Faraday modulation spectroscopy
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DOI：
10.1007/s00340-009-3602-0
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发表时间：
2009-08-01
影响因子：
2.1
通讯作者：
Muertz, M.
中科院分区：
文献类型：
--
作者：
Sabana, H.;Fritsch, T.;Muertz, M.
描述了一种基于连续分布反馈量子级联激光器(QCL)的法拉第调制光谱(FAMOS)同时检测(NO)-N-14和(NO)-N-15的技术。FAMOS是一种选择性、灵敏和时间分辨的光谱方法，用于在中红外光谱区对NO等自由基分子进行检测。所选择的谱线是位于1842.76 cm(-1)的(NO)-N-15的Q1.5和位于1842.93 cm(-1)的(NO)-N-14的P(9.5)。(NO)-N-15和(NO)-N-14的检出限分别为6 ppb/根赫兹和62 ppb/根赫兹。同时检测采用快速激光频率切换，时间分辨率为2 S，在800时，测得同位素比值(N-15)的精密度为0.52ppm，S测定100ppm NO的平均时间，时间分辨率为2S，用碘化钾从亚硝酸盐中释放NO，测定N-15。
We describe a technique of simultaneous detection of (NO)-N-14 and (NO)-N-15 by means of Faraday Modulation Spectroscopy (FAMOS) based on a cw distributed feedback quantum cascade laser (QCL) operating near 5.4 mu m. FAMOS is a spectroscopic method for selective, sensitive, and time-resolved detection of free radical molecules such as NO, in the mid-infrared spectral region. The selected spectral lines are the Q (1.5) for (NO)-N-15 located at 1842.76 cm(-1) and the P (9.5) for (NO)-N-14 located at 1842.93 cm(-1). The detection limit (1 sigma) of 6 ppb/root Hz for (NO)-N-15 and 62 ppb/root Hz for (NO)-N-14 has been achieved. The simultaneous detection was performed using a fast laser frequency switching between the two isotopologues with a time resolution of 2 s. The isotope ratio (delta N-15) has been determined with a precision (1 sigma) of 0.52 parts per thousand at 800-s averaging time for 100 ppm NO-gas with a time resolution of 2 s. delta N-15 is determined after NO release from nitrite by chemical reduction with potassium iodine.