title: [Direct fluorophotometric and flow-injection fluorophotometric methods for the determination of trace ammonia].
abstract: 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.
authors.affiliation: Chemistry Department of Fuzhou University, Fuzhou 350002, China.
authors.forename: Liang-qia
authors.initials: LQ
authors.lastname: Guo
authors.forename: Zeng-hong
authors.initials: ZH
authors.lastname: Xie
authors.forename: Xu-cong
authors.initials: XC
authors.lastname: Lin
authors.forename: Zi-hou
authors.initials: ZH
authors.lastname: Ke
authors.forename: Guo-nan
authors.initials: GN
authors.lastname: Chen
mesh_terms: 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
chemical_list: D008623:Mercaptoethanol; D000641:Ammonia