Possanzini Massimiliano, Di Palo Vincenzo
Istituto sull'Inquinamento Atmosferico CNR, Area della Ricerca Roma-1, Via Salaria km 29.3 - C.P. 10, I-00016 Monterotondo Scalo RM, Italia.
Ann Chim. 2003 Jan-Feb;93(1-2):149-56.
Formaldehyde, acetaldehyde, ozone and nitrogen dioxide in ambient air are simultaneously collected on silica gel cartridges coated with 1-methyl-1-(2,4-dinitrophenyl)hydrazine (MDNPH), where the two aldehydes are derivatized to their respective hydrazones, while the two oxidants are converted into N-methyl-2,4-dinitroaniline (MDNA). The three products are then separated and quantified by HPLC with UV detection at 360 nm. The stoichiometric factors of the MDNPH reactions with O3 and NO2 in laboratory tests correspond to 2.0 +/- 0.1 moles of MDNA per mole of O(x) (O3 + NO2). The limits of detection (LOD) are 0.7 ppbv HCHO, 0.8 ppbv CH3CHO and 1.6 ppbv O(x) for 30 L (1 h) air sampled. The sampling performance is insensitive to relative humidities encountered in real atmospheres. When compared with Sep-Pak DNPH silica cartridges as well as with ozone photometric and nitrogen dioxide chemiluminescent analyzers, the proposed chromatographic method demonstrates a very good accuracy (12% for HCHO, 14% for CH3CHO and 7% for O(x), on the average) under field sampling conditions at concentrations lower than 3 and 1 ppbv, for HCHO and CH3CHO, respectively and ranging from 28 to 62 ppbv for O(x).
在涂有1-甲基-1-(2,4-二硝基苯基)肼(MDNPH)的硅胶柱上同时采集环境空气中的甲醛、乙醛、臭氧和二氧化氮，其中两种醛被衍生化为各自的腙，而两种氧化剂则转化为N-甲基-2,4-二硝基苯胺(MDNA)。然后通过高效液相色谱在360nm处进行紫外检测，对这三种产物进行分离和定量。实验室测试中MDNPH与O3和NO2反应的化学计量系数对应于每摩尔O(x)(O3+NO2)生成2.0±0.1摩尔MDNA。对于采集30L(1小时)空气样本，检测限(LOD)分别为0.7ppbv甲醛、0.8ppbv乙醛和1.6ppbv O(x)。采样性能对实际大气中遇到的相对湿度不敏感。与Sep-Pak DNPH硅胶柱以及臭氧光度分析仪和二氧化氮化学发光分析仪相比，在现场采样条件下，对于甲醛浓度低于3ppbv、乙醛浓度低于1ppbv以及O(x)浓度在28至62ppbv范围内，所提出的色谱方法显示出非常好的准确度(平均而言，甲醛为12%，乙醛为14%，O(x)为7%)。
