Departamento de Química Analítica y Alimentaria, Área de Química Analítica, Facultad de Química, Universidad de Vigo, Vigo, Spain.
Talanta. 2011 Sep 15;85(3):1448-52. doi: 10.1016/j.talanta.2011.06.030. Epub 2011 Jun 17.
A miniaturized method based on liquid-phase microextraction (LPME) in combination with microvolume UV-vis spectrophotometry for monitoring ammonia in waters is proposed. The methodology is based on the extraction of the ion pair formed between the blue indophenol obtained according to the Berthelot reaction and a quaternary ammonium salt into a microvolume of organic solvent. Experimental parameters affecting the LPME performance such as type and concentration of the quaternary ammonium ion salt required to form the ion pair, type and volume of extractant solvent, effect of disperser solvent, ionic strength and extraction time, were optimized. A detection limit of 5.0 μg L(-1) ammonia and an enrichment factor of 30 can be attained after a microextraction time of 4 min. The repeatability, expressed as relative standard deviation, was 7.6% (n=7). The proposed method can be successfully applied to the determination of trace amounts of ammonia in several environmental water samples.
提出了一种基于液相微萃取（LPME）与微量紫外可见分光光度法相结合的微型方法，用于监测水中的氨。该方法基于将Berthelot 反应得到的蓝色靛酚与季铵盐形成的离子对萃取到微体积有机溶剂中。优化了影响 LPME 性能的实验参数，如形成离子对所需的季铵盐的类型和浓度、萃取溶剂的类型和体积、分散剂溶剂的影响、离子强度和萃取时间。经过 4 分钟的微萃取时间，可达到 5.0μg/L(-1)氨的检测限和 30 的富集因子。重复性表示为相对标准偏差为 7.6%（n=7）。该方法可成功应用于几种环境水样中痕量氨的测定。
