[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.
Guo
Liang-qia
LQ
Chemistry Department of Fuzhou University, Fuzhou 350002, China.
Xie
Zeng-hong
ZH
Lin
Xu-cong
XC
Ke
Zi-hou
ZH
Chen
Guo-nan
GN
D000641:Ammonia / Q000032:analysis*; D002138:Calibration; D002384:Catalysis; D017022:Flow Injection Analysis / Q000379:methods*; D015590:Fluorophotometry / Q000379:methods*; D008623:Mercaptoethanol / Q000737:chemistry; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods
D008623:Mercaptoethanol; D000641:Ammonia