| To develop those methods that are rapid, automatic, simple, economic and with high sensitivity (atom or molecule grade), high selectivity (complex system) is the direction of analytical chemistry. Analytical instrument is more and more automatized, digital applied, intelligentized, and contacted with information. It is still the basement of spectroscopic analysis to explore new color development reagent, recognition reagent for ion or molecule.artificial simulation eazyme, and enhancement reagent. To reconstruct the original molecule structure, modify the function group, develop new reaction system, optimize reaction condition, and control reaction speed, that is to say, to improve the analytical ability of the reaction and simplify the procedure, is also the most active study area, the most basal work.According to the above objections, we developed a set of researchers in the two aspects, which are to find effective enhancement reagent and to develop simple and sensitive detection methods.The property of dopamine in acid-alkaline medium was studied by spectrofluorimetry and spectrophotometry. A fluorescence quenching reaction took place in basic medium. Mechanism of fluorescence quenching was discussed. Effects of organic solvents on dopamine fluorescence spectra were examined and the reason was discussed. Among the organic solvents tested, methanol was selected as sensitizing reagent. A simple, rapid and highly sensitive fluorimetric method for the determination of dopamine in injection and urine is developed.Based on the reaction of dopamine with sodium nitrite in aqueous medium, in which product has a maximum absorption at 300 nm. and the reaction of dopamine with mercuric nitrate in aqueous medium, in which product has a maximum absorption at 240 nm, two simple and accurate spectrophotometric methods were described for the determination of dopamine.Dopamine was oxidized by mercuric nitrate, the oxidation product condensed with ethylenediamine to form a condensation product, which was transformed to a stable reagent after heating for 10 min at an acidic medium in a boiling water bath and the final product emitted high fluorescence. Under optimum condition, a linear relationship was obtained between the fluorescence intensity and the concentration of dopamine in the range of 0 to 0.6 Mgrn.!"1. The detection limit of this method is 18.3 ngml"1. The method is simple and can be used for the determination of dopamine in injection of dopamine and urine sample. The results obtained by this method agree with those by the official method.Use of fluorescence spectrophotometry for determination of procaine hydrochloride in injection solution of procaine hydrochloride is suggested based on fluorescence property of 4-aminobenzoate which is a hydrolysis product of the procaine hydrochloride in pH 12. |
