| In recent years,the rapid development of science,technology and heavy industry has bringing great convenience to people's life,but accompanied by environmental pollution at the same time.In industrial waste water,the emission of metal ions was increasing seriously,when these metal ions entered into the human body through various channels,a variety of diseases generated.Therefore,detecting of metal ions accurately and rapidly has become the research emphasis at present.Since the 90 s of last century,resonance Rayleigh scattering technology(RRS)as a new analysis mean was gradually paid more attention by many scholars at home and abroad.And some inorganic ions can combined with some macromolecular compounds to form binary or multiple ion association which can result to the resonance Rayleigh scattering intensity of system enhanced significantly.So the method can be used to determination metal ions.Because molybdenum(?)can be interact with the triphenylmethane dyes to form of multiple ion association,so the method can be used to detect molybdenum in the samples.At the same time,due to the strong fluorescence of quinone imine dyes,fluorescence can be used to detect cerium,lanthanum and copper in different samples,the specific contents are as follows:(1)The introduction mainly introduced the importance of detecting metal ions,the structural properties of triphenylmethane and quinone imine dyes and their applications in metal ion detection.At the same time,the development history of resonance Rayleigh scattering method and application of fluorescence spectrophotometry are also discussed.(2)Two new systems for the determination of molybdenum were established by resonance Rayleigh scattering method,which were Mo(?)-catechol violet-crystalline violet system and Mo(?)-salicylfluorone-hexadecyl bromide picoline system respectively.For the Mo(?)-catechol violet-crystalline violet system,in the pH = 3.5 potassium hydrogen phthalate-hydrochloric acid buffer solution,polyvinyl alcohol as a surfactant,molybdenum(?)can combined with pyrocatechol violet(PV)to form an anionic complex which further interacted with crystal violet(CV)cations with strong resonance Rayleigh scattering intensity at 647 nm.Therefore,A new method for the determination of trace of molybdenum(?)was established based on the resonance Rayleigh scattering spectra.The resonance Rayleigh scattering intensity was shown good linear relationship with concentration of molybdenum(?)in the range of 0.10~0.60 ?g/mL.The detection limit was1.5×10-4?g/m L.For the Mo(?)-salicylfluorone-cetylpyridinium bromide system,in the pH = 3.4 oxalic acid-ammonium oxalate buffer solution,Mo(?)combined with salicylfluorone(SAF)formed red complexes which can further interacted withcetylpyridinium bromide with strong resonance Rayleigh scattering intensity at the wavelength of 486 nm and 595.5nm,respectively.the resonance Rayleigh scattering intensity shown good linear relationship with concentration of Mo(?)in the range of0.024~0.088mg/mL.The detection limits were 2.76×10-2 ?g/mL and 3.54×10-2 ?g/mL,respectively.We also have detected of molybdenum in water samples,and explored the ion interferences of system.This chapter also discusses the mechanism of the two reaction systems.(3)Two new systems for determination trace of cerium(?)were established by rhodamine B(RhB)and rhodamine 6G(Rh6G)as fluorescent probes and cerium(?)as quenchers.Under the condition of H2SO4,rhodamine B and rhodamine 6G were combined with cerium(?)to form non-fluorescent substances,which caused the fluorescence quenching.The fluorescence intensity of rhodamine 6G and rhodamine B decreased with the increase of cerium(?)in a certain concentration range,and the relative fluorescence intensity of each system have a good linear relationship with the ion concentration.The linear ranges of Rhodamine 6G system and Rhodamine B system were 0.12~1.08?g/mL and 0.4~5.6?g/mL respectively.The detection limits were 1.4×10-3?g/mL and 4.6×10-3?g/mL,respectively.The samples were analyzed and the interference ions of the two reaction systems was discussed.This paper also discusses the reaction mechanism.(4)two new systems of catalytic kinetic fluorimetric methods for the determination of trace of lanthanum(?)were established.The experimental results showed that the rare earth element lanthanum(?)has a certain catalytic effect on the reaction of potassium bromate with the safranine T and the phenosafranine.So,two systems for the determination of trace lanthanum(?)were established.Under the optimum experimental conditions,the reaction rate of KBr O3 oxidation of safranine T and phenosafranine were gradually accelerated with the increase of lanthanum(?)in the system,and the fluorescence quenching degree of reaction system increased respectively.And the relative fluorescence intensity of each system shown good linear relationship with concentration of lanthanum(?)in the range of0.04~2.0?g/mL and 4.0~16?g/mL,respectively.The detection limits were 3.6×10-3?g/mL and0.334 ?g/mL,respectively.By compared two results,it was found that the safranine T system with higher sensitivity,so the interference ions of the safranineT system were measured.At the same time,the mechanism of the reaction of the systems was discussed.(5)Two new systems for the determination of trace copper were established based on the catalytic effect of copper ions.That are Cu(?)-potassium bromate-rhodamine B system and Cu(?)-hydrogen peroxide – safranine O system respectively.Cu(?)has a significant catalytic effect on the oxidation of rhodamine B with potassium bromate.and with theincreasing of Cu(?),the reaction rate was accelerated and the fluorescence quenching degree of rhodamine B was increased gradually.And the linear range was 0.20~1.40?g/mL.The detection limit was 2.0×10-5?g/mL.It can be found that similar to Cu(?)-potassium bromate-rhodamine B system,the linear range of Cu(?)-hydrogen peroxide-safranine O system was 0.5ng/mL to 12.5 ng/mL with a detection limit of 1.62×10-4ng/mL. |
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