| The improvement of living standard makes people pay more and more attention to various safety issues.The content of metal ions in wastewater discharge is increasing day by day,and when the human body absorbs too many metal ions,it will cause damage to body functions.Fluorescence analysis is a quantitative and qualitative analysis by analyzing the concentration of the substance to be measured in a certain range with a certain linear relationship with the luminescence intensity.This method has good sensitivity,sufficient selectivity and tolerance to foreign ions,and is widely used because of its simplicity,rapidity,sensitivity and accuracy.This thesis utilizes the ability of metal ions to cooperate with chromogenic agents or catalyze the oxidation of chromogenic agents,thus completing the detection of metal ions,as described below:（1）The introductory section briefly outlines the importance of metal ion determination and the determination of common analytical methods,and gives examples of different methods,focusing on the principles and classification of fluorescence analysis methods,the content of this study and its significance.（2）The systems for the fluorometric determination of tin complexes were established as Sn（II）-salicylidene fluorescence ketone-CTMAB,Sn（IV）-4-nitroazobenzenesalicylidene fluorescence ketone-CTMAB,and the maximum excitation and emission wavelengths of the systems wereλex/λem=503 nm/535 nm andλex/λem=455 nm/552 nm,respectively.4-nitroazobenzenesalicylidene fluorescence ketone was synthesized as a new chromogenic agent,and the 1H NMR and IR spectra of this chromogenic agent were analyzed,and the results obtained were consistent with the target compounds.The maximum absorption peak positions of the UV spectra of both reaction systems were changed,indicating the formation of complexes.It is speculated that the possible reaction mechanism is that tin can form ternary complexes with the reagents of fluorescent ketones in a strongly acidic medium under the electrostatic force of CTMAB.By determining the optimal experimental conditions,the standard working curves and detection limits of the two systems（0.0764μg/m L and 0.0771μg/m L,respectively）were derived,and the composition ratios of the complexes were investigated,which were 1:4:4 and1:2:4,respectively.TheΔF values showed good linearity in the range of 0～0.40μg/m L and1.5～3.5μg/m L,respectively.Compared with the spectrophotometric method,this method detected a wider linear range.The selectivity of the method was investigated and it was shown that the tin content in the samples could be determined directly without separation,and the tin ions in water and can samples were detected accordingly with the sample recoveries of95.83%～104.17%and 99.42%～103.38%,respectively.（3）Two fluorometric systems were developed for the determination of Mn.System I was a mangiferin fluorescence burst method,in which Mn（II）was able to catalyze the oxidation of mangiferin by oxygen in air in a borax-sodium hydroxide buffer solution at p H=9.50,leading to a kinetic reaction process of mangiferin fluorescence burst,λex/λem=463 nm/548 nm.System II was a new fluorescent ketone synthesized by hydrogen peroxide-catalyzed oxidation The reagent o-vanillin fluorescence ketone was determined as manganese,and in alkaline medium,Mn（II）was able to accelerate the oxidation of o-vanillin fluorescence ketone by hydrogen peroxide,λex/λem=495 nm/578 nm.Both systems showed a good linear relationship between its concentration and the fluorescence lg（F0/F）orΔF value of the system when the amount of Mn（II）was added gradually,and the Mn（II）could be detected accordingly.content.The linear concentration range was 0.004～0.048μg/m L and the detection limit was 4.203×10-3μg/m L in system I.The linear concentration range was 0.005～0.025μg/m L and the detection limit was 3.690×10-3μg/m L in system II.Compared with the spectrophotometric method,this method has a wider linear range,and most of the ions have no effect on the experimental results.By comparing the two systems,the better system II was selected for the determination of Mn（II）content in tap water,tea water and Yellow River water with the sample recoveries ranging from99.05%to 103.32%,and the reaction mechanism was investigated.（4）A catalytic kinetic fluorometric system was established for the determination of chromium.Alizarin red and catechol violet were selected as chromogenic agents,and the reactions were carried out in acidic HAc-Na Ac buffer solution medium,in which hydrogen peroxide could oxidize the chromogenic agent to make it fade,and Cr（VI）could accelerate the oxidation process,and the fluorescence intensity of both systems was reduced,and the maximum excitation and emission wavelengths of the systems wereλex/λem=470 nm/570 nm andλex/λem=499 nm/540 nm,respectively.The maximum excitation and emission wavelengths of the two systems wereλex/λem=470 nm/570 nm andλex/λem=499 nm/540nm,respectively,and the detection limits were 0.0642μg/m L,0.0659μg/m L and 0.0659μg/m L,respectively,when different volumes of Cr（VI）were added under the optimal experimental conditions,The linear range of this method was wider than that of the spectrophotometric method,with limits of detection of 0.0642μg/m L and 0.0659μg/m L,respectively.The more sensitive alizarin red system was selected for the detection of Cr（VI）ions in tap water,Yellow River water and soil after the treatment of interfering ions by comparison,and the sample recoveries ranged from 97.03%to 106.35%,and the reaction mechanism was investigated. |
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