| Resonance Rayleigh scattering(RRS)and resonance non-linear scattering are the new analytical technique developed in recent years.Because of their high sensitivity,cheapness instrument,simple operation and rapid analysis speed,these methods catch people's more attention and have been widely used to study of biological macromolecules such as nucleic acids, proteins and saccharide and determination of trace metal ions,nonmetal ions,nanoparticle and some pharmaceuticals.In this work,the application of RRS and RNLS to analysis of folic acid and methotrexate were studied the spectral characteristics,optimum reaction conditions,influencing factors and and the properties of analytical chemistry have been studied.Some new methods for the determination of folic acid and methotrexate by RRS and RNLS techniques have been developed.The reaction mechanism and the reasons of the RRS enhancement have been discussed.1.Effects of Interaction of Folic acid with Uranium(Ⅵ)and Basic Triphenylmethane Dyes on the Absorption and Resonance Rayleigh Scattering Spectra and Their Analytical Application In Britton-Robinson buffer of pH 4.2-4.8,folic acid react with Uranium(Ⅵ)to form 2:1 anionic chelates.Which further react with basic triphenylmethane dyes(BTPMD)such as Ethyl Violet, Methyl Violet and Crystal Violet to form 1:2 ion-association complexes.Then the dyes discoloration obviously,and the absorption spectra changed.The great enhancements of RRS intensities are observed and new RRS spectra appear.Their spectral characteristics of the three systems are similar, the maximum fading wavelengths were situated at 545 nm(EV system),574 nm(MV system)and 589 nm(CV system).The maximum RRS wavelengths are all at 328 nm.But the intensities of dyes are some difference,ether discoloration or RRS as Ethyl Violet system(EV)＞Methyl Violet system(MV)＞Crystal Violet system(CV).Under given conditions the intensities of RRS and fade of the absorption are all proportional to the consistence of FA,The linearity range and limits of three fading spectrophotometer systems are 0.21-7.0μg/mL and 62.0 ng/mL(EV system);0.24-4.0μg/mL and 71.0 ng/mL(MV system);0.35-6.0μg/mL and 104.0 ng/mL,respectively.The linearity range and limits of three RRS systems are 0.004 -5.0μg/mL and 1.2 ng/mL(EV system);0.013-4μg/mL and 2.2 ng/mL(MV system);0.025-4.0μg/mL and 3.7 ng/mL(CV system).All the three RRS systems can be used determinate trace FA more sensitive and more suitable.The optimum conditions of the reaction and influence factors and the effect of coexisting substances on the reaction were investigated.A high sensitive,simple and fast method is proposed to the determination of FA.The method can be used satisfactorily for determination of FA in serum and urine samples.The composition for the ternary ion-association complex is investigated,and the structure of the complex and its reaction mechanism are discussed.2.Resonance Rayleigh scattering spectra and resonance non-linear scattering of Fe(Ⅲ)-folic acid system and its analytical applicationIn pH 5.0 HAc-NaAc buffer solution,folic acid(FA)can react with Fe(Ⅲ)to produce Fe(Ⅱ),and the Fe(Ⅱ)will reacted with FA to form chelate,which lead to the significant enhancement of resonance Rayleigh scattering(RRS)and non-linear scattering such as second-order scattering(SOS) and frequency doubling scattering(FDS).The maximum scattering wavelengths were 398 nm for RRS,580 nm for SOS and 390 nm for FDS,respectively.The scattered intensity increments(△/)of five products were directly proportional to the concentrations of antibiotics in certain ranges.The linear ranges and detection limits for FA were 0.033-8.0μg/mL and 9.8 ng/mLfor RRS method, 0.049-6.0μg/mL and 14.6 ng/mL for SOS method,and 0.035-5.0μg/mL and 10.6 ng/mL for FDS method.Among them,the RRS method exhibited the highest sensitivity.In this work,the reaction conditions of RRS method and the influencing factors were investigated.The effects of coexisting substances were examined indicating that the method had a good selectivity.Based on the above researches,a highly sensitive,simple and fast method for the indirect determination of FA has been developed.It was applied in the determination of FA in human serum and urine samples.3.Resonance Rayleigh scattering spectra of the interaction of Pd(Ⅱ)- methotrexate chelate with some basic phenothiazine dyes and their analytical applicationIn Britton-Robinson buffer of pH 4.1-7.0,methotrexate reacts with palladium(Ⅱ)to form 1:1 anionic chelates,which react further with methylene blue(MB),toluidine blue(TB)and azur A(Az A) to form the ion-association complexes,In this case,the resonance Rayleigh scattering(RRS) intensities are enhanced greatly and new RRS spectra appear.Their characteristics of RRS spectra are similar,and the maximum RRS wavelengths are all at 330 nm.But the RRS intensities of the ion-association complexes are different depending on used dye.The order of the relative scattering intensities are MB system＞TB system＞Az A system.Under given conditions the intensities of RRS are proportional to the concentration of MTX.The linear ranges are 0.008-2.0μg/mL,0.013-3.5μg/mL,0.025-4.0μg/mL for MB system,TB system,Az A system,respectively.The methods have high sensitivities the detection limits of MTX are 2.5 ng/mLfor MB system,3.9 ng/mLfor TB system and 7.6 ng/mLfor Az A system.The optimum conditions of the reaction,influence factors and the effect of coexisting substances have been investigated.A high sensitive,simple and quick method is developed to the determination of MTX.The method can be applied satisfactorily to determination of MTX in some samples.In addition,the structure of the ternary ion-association complex and their reaction mechanism were discussed.4.Second-order scattering and frequency doubling scattering spectra of TI(Ⅲ)-methotrexate system and its analytical applicationIn pH 4.9 Britton-Robinson(BR)buffer solution,methotrexate reacted with thallium(Ⅲ)to form 3:1 chelate.In this case,the second-order scattering spectra(SOS)and frequency doubling scattering spectra(FDS)intensities are enhanced greatly.The maximum SOS and FDS wavelength were located at 520 nm and 390 nm,respectively.The linearity ranges of the system are 0.022-2.0μg/mL(SOS method)and 0.008-2.5μg/mL(FDS method),and the methods have high sensitivities the detection limits of MTX are 7.4 ng/mL and 2.3 ng/mL,respectively.The optimum conditions of the reaction,influence factors and the effect of coexisting substances have been investigated.A high sensitive,simple and quick method was developed to the determination of MTX.The method can be applied satisfactorily to determination of MTX in serum and urine samples.In this study,the MTX charge distribution was calculated by CNDO quantum chemistry method.The reaction mechanism was discussed.5.Resonance Rayleigh scattering spectra of Tl(Ⅲ)- Methotrexate system and its analytical applicationIn a Britton-Robinson(BR)buffer solution of pH 4.9,methotrexate reacts with thallium(Ⅲ)to form 3:1 chelate.In this case,the RRS intensities are enhanced greatly and new RRS spectra appear. The maximum RRS wavelength is locate at 335 nm,and at 366 nm there is another strong RRS peak. The linearity range of the system is 0.010-2.5μg/mL,and the methods have high sensitivities the detection limits of MTX is 3.1 ng/mL,the method also have a good selectivity.A high sensitive, simple and quick method was developed to the determination of MTX.The method can be applied satisfactorily to determination of MTX in serum and urine samples.6.Resonance Rayleigh scattering method for the determination of folic acid and methorexate with 12- tungstophosphoric acid probeIn pH 0-1.5 HCl medium,folic acid(FA)and methotrexate(MTX)react with 12-tungstophosphoric acid to form 3:1 complex.In this case,the RRS intensities are enhanced greatly and new RRS spectra appear.The maximum RRS wavelength is locate at 370 nm for FA,and 368 nm for MTX.The linearity ranges and the detection limits are 0.056-5.0μg/mL and 11.2 ng/mL for FA,0.021-3.0μg/mL and 6.3 ng/mL for MTX,and the determination of MTX exhibited the higher sensitivity.Taking MTX as an example,the effects of coexisting substances were examined indicating that the method had a good selectivity.A high sensitive,simple and quick method was developed to the determination of MTX and FA.The method can be applied satisfactorily to determination of MTX in serum and urine samples.
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