Quantification of nitryl chloride at part per trillion mixing ratios by thermal dissociation cavity ring-down spectroscopy.
Quantification of nitryl chloride at part per trillion mixing ratios by thermal dissociation cavity ring-down spectroscopy.
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DOI：
10.1021/ac200055z
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发表时间：
2011-03
影响因子：
7.4
通讯作者：
Robert D Thaler;L. Mielke;H. Osthoff
中科院分区：
文献类型：
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作者：
Robert D Thaler;L. Mielke;H. Osthoff
氯化硝基化合物(ClNO(2))是对流层中重要的夜间氮氧化物储存体。在这里，我们报道了一种新的方法，热解离腔衰荡光谱(TD-CRDS)，以定量的ClNO(2)混合比具有数十万亿分之一的体积灵敏度(PPTV)。用蓝光半导体激光器CRDS测定了在加热到450℃的进气口中由ClNO(2)定量热解产生的NO(2)的混合比，相对于在未加热的参考通道中观察到的NO(2)。ClNO(2)是通过在含有NaNO(2)和氯化钠的1：10混合物的浆液上通过氯(2)气体而产生的。用I(-)为试剂离子和NO(Y)(=NO+NO(2)+HNO(3)+ΣRO(2)NO(2)+ΣRONO(2)+HONO+2N(2)O(5)+ClNO(2)+…)，用化学电离质谱仪平行测量ClNO(2)对TD-CRDS的响应。化学发光(CL)。线性动态范围从20pptv(1σ，1min)的检测下限扩展到30ppbv(以体积计)，这是所测试的最高混合比。ClNO(2)TD谱与烷基硝酸盐的TD谱重叠，这对通过热解离(检测为NO(2))夜间测量环境空气中总烷基硝酸盐(ΣAn=ΣRono(2))的丰度具有重要意义。
Nitryl chloride (ClNO(2)) is an important nocturnal nitrogen oxide reservoir species in the troposphere. Here, we report a novel method, thermal dissociation cavity ring-down spectroscopy (TD-CRDS), to quantify ClNO(2) mixing ratios with tens of parts-per-trillion by volume (pptv) sensitivity. The mixing ratios of ClNO(2) are determined by blue diode laser CRDS of NO(2), produced from quantitative thermal dissociation of ClNO(2) in an inlet heated to 450 °C, relative to NO(2) observed in an unheated reference channel. ClNO(2) was generated by passing Cl(2) gas over a slurry containing a 1:10 mixture of NaNO(2) and NaCl. The TD-CRDS response was evaluated using parallel measurements of ClNO(2) by chemical ionization mass spectrometry (CIMS) using I(-) as the reagent ion and NO(y) (= NO + NO(2) + HNO(3) + ΣRO(2)NO(2) + ΣRONO(2) + HONO + 2N(2)O(5) + ClNO(2) + ...) chemiluminescence (CL). The linear dynamic range extends from the detection limit of 20 pptv (1 σ, 1 min) to 30 parts-per-billion by volume (ppbv), the highest mixing ratio tested. The ClNO(2) TD profile overlaps with those of alkyl nitrates, which has implications for nocturnal measurements of total alkyl nitrate (ΣAN = ΣRONO(2)) abundances by thermal dissociation (with detection as NO(2)) in ambient air.