Department of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.
Anal Chem. 2011 Apr 1;83(7):2761-6. doi: 10.1021/ac200055z. Epub 2011 Mar 10.
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.
亚硝酰氯（ClNO(2)）是对流层中一种重要的夜间氮氧化物储库物种。在这里，我们报告了一种新方法，即热解离腔衰荡光谱（TD-CRDS），该方法具有体积数十 pptv（1 西格玛，1 分钟）的检测限，可实现亚硝酰氯混合比的定量检测。亚硝酰氯的混合比通过在 450°C 加热的入口中定量热解离 ClNO(2)产生的二氧化氮（NO(2)）的蓝二极管激光 CRDS 来确定，相对于在未加热的参考通道中观察到的 NO(2)。ClNO(2)是通过将 Cl(2)气体通过含有 1:10 混合物的 NaNO(2)和 NaCl 的浆料来产生的。使用 I(-)作为试剂离子的化学电离质谱（CIMS）对 ClNO(2)进行平行测量，通过化学电离质谱（CIMS）评估了 TD-CRDS 响应，并用 NO(y)（=NO+NO(2)+HNO(3)+ΣRO(2)NO(2)+ΣRONO(2)+HONO+2N(2)O(5)+ClNO(2)+...）化学发光（CL）进行测量。线性动态范围从检测限 20 pptv（1σ，1 分钟）扩展到 30 体积 ppmb（体积百万分之一），这是测试的最高混合比。ClNO(2)TD 谱与烷基硝酸盐重叠，这对环境空气中通过热解离（检测为 NO(2))测定总烷基硝酸盐（ΣAN=ΣRONO(2))的丰度具有重要意义。
