Measurement of airborne carbonyls using an automated sampling and analysis system.
Measurement of airborne carbonyls using an automated sampling and analysis system.
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DOI：
10.1021/es901892f
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发表时间：
2009-10
影响因子：
11.4
通讯作者：
Mauro Aiello;R. McLaren
中科院分区：
文献类型：
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作者：
Mauro Aiello;R. McLaren
基于成熟的2，4-二硝基苯肼衍生化方法，通过自动化、直接进样和连续使用单个微型二氧化硅DNPH色谱柱，开发了一种环境中羰基化合物的测量仪器，大大提高了时间分辨率和检测限。动力学实验表明，色谱柱上的衍生化反应速度足够快，可用于50min空气采样的连续测量。试剂盒上测得的甲醛、乙醛、丙醛、丙酮和苯甲醛等羰基化合物的反应效率为100%。通过臭氧洗涤器(KI)的羰基透过率在97-101%的范围内。空白水平和检测下限比传统的DNPH方法低一个数量级或更多。环境空气中羰基化合物的混合比检测下限为38-73ppt/50分钟空气样本(2.5 L)。在安大略省西南部的一项实地研究中，该仪器在10天内以2小时为周期连续测量了羰基。混合比例的中位数为0.58 ppb甲醛、0.29 ppb乙醛、1.14 ppb丙酮和0.45 ppb乙二醛。乙二醛与臭氧和零截获有显著的相关性，与大气的次要来源和次要的直接来源一致。该方法应该可以很容易地扩展到以前报道的使用DNPH技术的其他低分子羰基的检测。
Based upon the well established method of derivitization with 2,4-dinitrophenylhydrazine, an instrument was developed for ambient measurement of carbonyls with significantly improved temporal resolution and detection limits through automation, direct injection, and continuous use of a single microsilica DNPH cartridge. Kinetic experiments indicate that the derivitization reaction on the cartridge is fast enough for continuous measurements with 50 min air sampling. Reaction efficiencies measured on the cartridge were 100% for the carbonyls tested, including formaldehyde, acetaldehyde, propanal, acetone, and benzaldehyde. Transmission of the carbonyls through an ozone scrubber (KI) were in the range of 97-101%. Blank levels and detection limits were lower than those obtainable with conventional DNPH methods by an order of magnitude or greater. Mixing ratio detection limits of carbonyls in ambient air were 38-73 ppt for a 50 min air sample (2.5 L). The instrument made continuous measurements of carbonyls on a 2 h cycle over a period of 10 days during a field study in southwestern Ontario. Median mixing ratios were 0.58 ppb formaldehyde; 0.29 ppb acetaldehyde; 1.14 ppb acetone; and 0.45 ppb glyoxal. Glyoxal shows a significant correlation with ozone and zero intercept, consistent with a secondary source and minor direct source to the atmosphere. The method should easily be extendable to the detection of other low molecular weight carbonyls that have been previously reported using the DNPH technique.