Huang Gu, Hou Jian, Zhou Xianliang
Department of Environmental Health and Toxicology, School of Public Health, State University of New York at Albany, Albany, New York, USA.
Environ Sci Technol. 2009 Aug 1;43(15):5851-6. doi: 10.1021/es900988q.
A method of precolumn derivatization HPLC with fluorescence detection has been developed for the measurement of ammonia, primary methylamine, ethylamine, propylamine, and butylamine in the atmosphere. Air samples were collected by two continuously wetted glass frit/coil samplers, one directly from ambient air for the sum of gaseous and aerosol species, and the other after an acid-coated annular denuder for the aerosol species. The collection efficiency for all analytes was found to be > or = 99% at a sampling gas flow rate of 2 L min(-1) and a scrubbing water flow rate of 0.24 mL min(-1). The collected ammonia and primary amines were derivatized with o-phthalaldehyde (OPA) and n-acetyl-cysteine (NAC) reagents in an in-line derivatization coil to form highly fluorescent sulfonatoisoindole derivatives. Detailed kinetic study showed that derivatization reactions were fast but the derivatives were not very stable. Derivatization conditions, such as reagent concentrations, derivatication medium pH, and derivatization time, were optimized to achieve maximum derivative yields for all the analytes. The derivatives were separated on a C-18 reverse-phase column using a gradient elution and detected by a fluorescence detector at an excitation wavelength of 330 nm and an emission wavelength of 471 nm. The respective lower detection limits for ammonia and for the four primary amines were 24 parts per trillion by volume (pptv) and < or = 3 pptv, with a sample time resolution of about 1 min and a sampling/ analysis time of 20 win per cycle. The analytical methodology has been applied in the field measurements; results from two case studies are presented.
已开发出一种采用荧光检测的柱前衍生化高效液相色谱法，用于测定大气中的氨、甲胺、乙胺、丙胺和丁胺。空气样品通过两个连续湿润的玻璃料/盘管采样器采集，一个直接采集环境空气中的气态和气溶胶态物质总和，另一个在经过酸涂层环形去溶器后采集气溶胶态物质。发现在采样气体流速为2 L min⁻¹和洗涤水流速为0.24 mL min⁻¹时，所有分析物的采集效率均≥99%。采集到的氨和伯胺在在线衍生化盘管中用邻苯二甲醛（OPA）和N-乙酰半胱氨酸（NAC）试剂进行衍生化，形成高荧光的磺基异吲哚衍生物。详细的动力学研究表明，衍生化反应很快，但衍生物不太稳定。对衍生化条件，如试剂浓度、衍生化介质pH值和衍生化时间进行了优化，以实现所有分析物的最大衍生物产率。衍生物在C-18反相柱上采用梯度洗脱进行分离，并用荧光检测器在激发波长330 nm和发射波长471 nm下进行检测。氨和四种伯胺各自的最低检测限分别为24体积万亿分之一（pptv）和≤3 pptv，样品时间分辨率约为1分钟，每个循环的采样/分析时间为20分钟。该分析方法已应用于现场测量；给出了两个案例研究的结果。
