直接荧光法和流动注射荧光法测定微量氨的研究

在碱性介质中 ,基于氨与邻苯二甲醛及 2 巯基乙醇反应生成强荧光性吲哚取代衍生物的体系建立测定水溶液中微量氨的直接荧光法和流动注射荧光法。曲通X 10 0 (TritonX 10 0 )对该体系具有良好的增稳作用。在λex=4 15nm ,λem=4 86nm下 ,用直接荧光法测定NH3含量在 0 2～ 1 0 μg·mL- 1 范围内 ,工作曲线的回归方程为ΔI =2 2 2 86 785 71cNH3(μg·mL- 1 ) (I即为Intensity) ,r=0 9995 ;NH3含量在 0 0 2～ 0 10 μg·mL- 1 范围内 ,工作曲线的回归方程为ΔI=- 2 7 4 2 9 2 371 4cNH3(μg·mL- 1 ) ,r=0 996 5。用流动注射法测定的工作曲线的回归方程为ΔI=1188cNH3(μg·mL- 1 ) ,r=0 9998,线性范围为 0～ 0 7μg·mL- 1 ,并对反应机理进行初步探讨。

Direct Fluorophotometric and Flow-Injection Fluorophotometric Methods for the Determination of Trace Ammonia

Direct fluorophotometric and flow-injection fluorophotometric methods for trace ammonia measurement involving the fluorescent reaction of ammonia with o-phthaldlaldehyde (OPA) and 2-mercaptoethanol (ME) producing derivant of iso-indol in alkaline solution are described. Triton X-100 was added to improve the stability of the system. The maximum excitation wavelength is 415 nm, while the maximum emission wavelength is 486 nm. With direct fliuorophotometric method, the calibration curve's regression equation is deltaI = 22.286 + 785.71c(NH3) (microg x mL(-1)) (r = 0. 9995) in the range of ammonia concentration from 0.2 to 1.0 microg x mL(-1), and deltaI = -27.429 + 2 371.4c(NH3) microg x mL(-1)) (r = 0.9965) in the range of ammonia concentration from 0.02 to 0.10 microg x mL(-1). With flow-injection fluorophotometric method, the calibration curve's regression equation is deltaI = 1188c(NH3) (microg x mL(-1)) (r = 0. 9998) in the range of ammonia concentration of ammonia 0-0.7 microg x mL(-1). The mechanism of reaction was also briefly discussed.