| Flow injection analysis (FIA), developed in 1975 by Ruzika and Hansen of the Technical University of Denmark, is a new analytical technique for sample solutions being effectively dealt with and determined in non-equilibrium state. It made the traditional concept of the "steady-state signal" in analytical chemistry be completely abandoned and a new field of solution analysis chemistry be inaugurated. In a flow injection system, some complicated pre-handling can be carried through, such as on-line separation or on-line conversion of analyte, that substantially enhances the performance of many traditional analytical methods, even has the whole analysis process automated.A series of new FIA methods are developed in this thesis based on pre-reaction, involving the techniques of on-line separation and on-line conversion, et al. and these methods have been applied to the analysis of real samples with satisfactory results.I. The basis of the on-line pre-reaction FIAThe developing process of FIA is outlined briefly first, especially those correlated closely with this work are reviewed in detail with 114 references cited, which comprise flame atomic absorption spectrometry (FAAS) for indirect determination, catalytic kinetics analysis, and the application of solid phase reactor (SPR) packed with inorganic reagents, etc. Then, through theoretical analysis, it is shown that adopting packed-SPR in a FIA system for pre-separation or pre-conversion of the analyte not only makes the flow manifolds be simplified, but also the shapes of signal output be improved, and the sensitivity and sampling frequency be enhanced.II. Column separation on-line flow injection flame atomic absorption spectrometry for indirect analysis (determinations of ciprofloxacin and COD)A novel flow injection flame atomic absorption spectrometry is proposed for the indirect analysis of ciprofloxacin, which is based on the formation of cation complex Fe(III)-ciprofloxacin, and on-line separation and concentration it with an ion exchange column. The linear range is over 5 - 100 ug mL-1 and 0.5 - 80 ug mL-1, at an analytical throughput of 30 and 22 samples per hour when the concentration times are 60 s and 100 s, respectively. This method has been applied to the analysis of ciprofloxacin in pharmaceutical preparations with satisfactory results.Adopting the same manifolds as above, a rapid method for the determination of chemical oxygen demand (COD) in environmental water samples is investigated, in which KMnO4 is as oxidant, and the Mn2+ produced is separated and concentrated with ion exchange column. The linearity ranges from 10 to 200 mg L-1 with the detection limit of 3 mg L-1 of COD. The analytical frequency is 24 samples per hour and the relative standard deviation is 3.4% (n=11). Up to 10,000 mg L-1 of Cl- dose not interfere for the determination. The method has been applied to the determination of COD in river water, pool and industrial waste waters. The results agree basically with those by classical potassium dichromate method.III. Pre-hydrolysis on-line flow injection spectrophotometic analysis(rapid determination of polysaccharide)A flow injection on-line hydrolysis spectrophotometry for rapid determination of polysaccharide is developed. In acid medium, polysaccharide is hydrolyzed on-line at 95 C, the hydrolyzed product reacts with 3,5-dinitrosalicylic acid to produce a red compound, then the absorbance of the compound is measured at 540 nm. The calibration curve is linear over a range from 20 to 150 ug mL-1 (expressed in glucose) with a correlation coefficient of 0.999. The detection limit is 10.0 ug mL-1 and thesampling frequent is 60 h-1 with a relative standard deviation <2.2% (n=7). The recovery ranges from 97% to 104%. The method has been applied to the determination of polysaccharide content in Ligusticum Chuanxiong Hort., and the result agrees with Dubois' method.IV. Pre-reduction on-line with solid phase reactor spectrophotometric analysis (simultaneous catalytic determination of nitrite and nitrate)A new fl...
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