Determination of Potassium Ferrocyanide in Foods by Resonance Rayleigh Scattering Method with Basic Triaminotriphenylmethane Dyes

In this work, a sensitive, rapid and simple method for the determination of trace amounts of potassium ferrocyanide in salinized foods and table salt using EV as a RRS probe is established. The detection limit （3σ） of the EV system is 7.8 ng/mL. This new method is more suitable for the determination of the trace amounts of potassium ferrocyanide in colour salinized foods and it can not be disturbed by the color of salinized foods.

Resonance Rayleigh Scattering and Resonance Nonlinear Scattering Methods for Determination of Methylene Blue with 12-Tungstophosphoric Acid

In a pH=0.65―1.5 NaAc-HCl medium, methylene blue（MB） reacts with 12-tungstophosphoric acid （TPA） by virtue of electrostatic attraction and hydrophobic force to form a 3：2 ion-association complex. As a result, the intensities of resonance Rayleigh scattering（RRS）, second-order scattering（SOS） and frequency doubling scatte- ring（FDS） are enhanced greatly. The maximum scattering wavelengths of RRS, SOS and FDS are located at 316, 647 and 311 nm. The increments of scattering intensity（△I） are directly proportional to the concentration of MB in a certain range. The methods exhibited high sensitivity, and the detection limits（3s） for MB are 2.3 ng/mL（RRS method）, 5.6 ng/mL（SOS method） and 6.4 ng/mL（FDS method）, respectively. The effects of coexisting substances have been examined, and the results indicate that the methods have good selectivity. Based on the above researches, a new spectral method for the determination of trace amounts of MB has been developed. It can be applied to the determination of MB in human serum, and the recoveries are 97.5%―105.0%. The results are in good agreement with those obtained by the pharmacopoeia method. In this work, the optimum conditions of the reaction and the influencing factors were investigated. In addition, the reaction mechanism and the reasons of the enhancement of resonance light scattering were discussed.

Determination of Matrine and Oxymatrine in Radix Sophorae Flavescentis by Resonance Rayleigh Scattering, Second-order Scattering and Frequency Doubling Scattering Technique

In 0.1 mol/L HCl medium, 12-tungstophosphoric（TP） acid reacted with matrine（Mat） and oxymatrine（Oxy） to form an ion-association complex. As a result, the new spectra of resonance Rayleigh scattering（RRS）, second-order scattering（SOS） and frequency doubling scattering（FDS） appeared and their intensities were enhanced greatly. The maximum scattering wavelengths of RRS, SOS and FDS were located at 370, 670 and 390 nm, respectively. The in-crements of scattering intensity were directly proportional to the concentration of Mat and Oxy in a certain range. Based on this, the method for the determination of matrine and oxymatrine has been established. It has been applied to the determination of matrine and oxymatrine in samples of Radix sophorae flavescentis with satisfactory result. The reaction mechanism and reasons of RRS enhancement were discussed.

Interaction Between Mitoxantrone Metal Complex and Titan Yellow by Resonance Rayleigh Scattering Spectra and Its Analytical Application

In a pH 2.4 Britton-Robinson buffer medium, the anthracycline antibiotics mitoxantrone（MXT） could react with metal ions such as Pd（Ⅱ）, Co（Ⅱ） and Cu（Ⅱ） to form 1：2（molar ratio） cationic chelates, which further reacted with the anionic dye titan yellow to form 1：2 ternary ion-association complexes by electrostatic interaction. As a result, the intensity of resonance Rayleigh scattering（RRS） was enhanced greatly. These RRS spectral characteristics of various metal ion systems were similar, and the maximum RRS wavelengths were all located at 454 nm. But the increments of RRS intensities were different in the series of Pd（Ⅱ）〉Co（Ⅱ）〉Cu（Ⅱ）. The enhanced RRS intensities were proportional to the concentration of MXT in a range of 0.03-2.4μg/mL and the detection limit（3σ） was 0.009μg/mL for the Pd（Ⅱ） system. In this study, the optimum conditions of the reactions and the effects of foreign substances were investigated, in addition, the composition and reaction mechanism of ion-association complexes were discussed. Thus a highly sensitive, simple and rapid method is proposed for the determination of MXT in urine and serum samples.

Study on Resonance Rayleigh Scattering Spectra of Mercaptopurine-Cu(II)-Nucleic Acid System

In pH 4.8 Britton-Robinson (B-R) buffer solution, Mercaptopurine (MP) could react with Cu(II) to form stable chelate compound, a new Resonance Rayleigh scattering (RRS) spectrum generated and enhanced for the binary system which the highest peak located at 453 nm as detection wavelength. But the RRS spectra could be quenched after adding her- ring milt DNA (hsDNA), salmon milt DNA (sDNA) and calf thymus DNA (ctDNA) into the binary system, respect- tively. And the weakened degree of spectra was directly proportional to the concentration of DNA. The reaction product of three nucleic acid system have identical spectral features, their range of linearity for the relation of spectral intensity with concentration respectively are 0.05 - 0.9 μg.mL-1 for hsDNA, 0.1 - 0.9 μg.mL-1 for sDNA and 0.3 - 0.9 μg.mL-1 for ctDNA;their detection limit respectively are 5 ng.mL-1for hsDNA, 6 ng.mL-1for sDNA, 6 ng?mL-1 for ctDNA. So a new method for determination of DNA was developed and successfully applied to determine the content of the DNA in artificial synthetized samples. At the same time the spectral features of absorption spectra and RRS spectra of the three reaction system, and the eligible reaction conditions and influencing factors were investigated in this paper.

A study on resonance Rayleigh scattering spectra of Humic Acid (HA)

This paper deals with the influences of pH, acidity and ionic intensity of the solutions on the resonance Rayleigh scattering spectra and fluorescence spectra of humic acid. When the pH value is low and the acidity and ionic intensity are high, the resonance Rayleigh spectra and fluorescence spectra both show a tendency of increasing, though the former's intensity is much higher. In combination with the transmission electron microscope data, the factors leading to the occurrence and enhancement of the resonance Rayleigh scattering spectra of humic acid were explored. It is considered that particle enlargement caused by aggregation, the increase of heterogeneity, the increase of hydrophobility, the formation of interface, etc., are the factors leading to the occurrence and enhancement of the resonance Rayleigh scattering spectra of humic acid. As the intensity of the resonance Rayleigh scattering spectra of humic acid is much higher, resonance Rayleigh scattering spectroscopy can be used as a newly developed spectrum technology, which is more sensitive and simpler, to study humic acid and its complicated behaviors.

Resonance Rayleigh scattering spectral characteristics of interaction of nucleic acids with some cationic surfactants and their analytical applications

In near neutral medium, the resonance Rayleigh scattering (RRS) intensities of an alone cationic surfactant and nucleic acid are very weak. However, when they combine with each other to form a complex, the RRS intensity of the solution is enhanced greatly. In this paper the reactions of five cationic surfactants with nucleic acids have been studied. The results show that the reaction conditions and RRS spectral characteristics of these reactions are similar, but their sensitivities are obviously different. Among them, the sensitivity of cetyldimethyl benzylammonium chloride (CDBAC) with an aryl and large molecular weight is the highest, while that of cetyltrimethylammonium bromide (CTAB) without aryl and with small molecular weight is the lowest. The detection limits for ctDNA and yRNA of the former are 6.6 and 29.4 ng@mL?1, while that of the latter are 13.3 and 53.6 ng@mL?1. The method has better selectivity and can be applied to the determination of trace amounts of nucleic acids. Furthermore, it is discovered in the investigation that not only the RRS intensity is related to the structure and molecular weight of the cationic surfactants, but also the change of the RRS intensity is closely related to the conformational change of nucleic acid. Therefore, the RRS method can be expanded to become a useful way to study the nucleic acid conformation.

Absorption and Rayleigh scattering and resonance Rayleigh scattering spectra of [HgX_2]_n nanoparticles

The composition and existing species of the reaction production of Hg2+ and X- (X= Cl, Br and l) under different conditions, and their absorption, Rayleigh scattering (RS) and resonance Rayleigh scattering (RRS) spectra have been studied. The results show that the products exist in the form of nanoparticles as [HgX2]n aggregates under suitable conditions, and their average diameters increase with the increase of X- diameters. The diameters of [HgCl2]n [HgBr2]n and [Hgl2]n are less than 4 nm, equal to 9 nm and 70 nm respectively. There are bathchromic shifts gradually with the increase of X- diameters in their absorption spectra. The absorption bands of [HgCl2]n and [HgBr2]n locate at ultraviolet region. However, the absorption band of [Hgl2]n is obvious in visible light region. Among three particles, only [Hgl2]n exhibits a strong RRS and its scattering peak is at 580 nm. The main reasons leading to the enhancement of resonance scattering are the large size of nanoparticle, the formation of the interface and the location of light scattering in the absorption band. There are three important factors affecting resonance scattering spectrum: the quanta colored effect and molecular absorption spectrum of [Hgl2]n nanoparticle as well as instrumental factors which mainly include the light source's emission spectral characteristics and the signal response curve of detector.

Study on the interaction between diphenhydramine and erythrosin by absorption,fluorescence and resonance Rayleigh scattering spectra

In pH 4.5 Britton-Robinson(BR)buffer solution,erythrosin(ET)can react with diphenhydramine(DP)to form a 1:1 ion-association complex,which not only results in the change of the absorption spectra,but also results in the great enhancement of resonance Rayleigh scattering(RRS)and the quenching of fluorescence.Furthermore,a new RRS spectrum will appear,and the maximum RRS wavelength was located at about 580 nm.In this work,the spectral characteristics of the absorption,fluorescence and RRS,the optimum conditions of the reaction and the properties of an analytical chemistry were inves- tigated.A sensitive,simple and new method for the determination of DP by using erythrosin as a probe has been developed.The detection limits for DP were 0.0020μg/mL for RRS method,0.088μg/mL for absorption method and 0.094μg/mL for fluorophotometry.There was a linear relationship between the absorbance,RRS and fluorescence intensities and the drug concentration in the range of 0.0067-2.0, 0.29-6.4 and 0.31-3.2μg/mL,respectively.The effects of the interaction of diphenhydramine and erythrosin on the absorption,fluorescence and resonance Rayleigh scattering spectra were discussed. In light polarization experiment,the polarization of RRS at maximum wavelength was measured to be P =0.9779,and it revealed that the RRS spectrum of DP-ET complex consists mostly of resonance scat- tering and few resonance fluorescence.In this study,enthalpy of formation and mean polarizability were calculated by AM1 quantum chemistry method.In addition,the reaction mechanism and the rea- sons for the enhancement of scattering spectra and the energy transfer between absorption,fluores- cence and RRS were discussed.

Study on the absorption and fluorescence and resonance Rayleigh scattering spectra of Cu (II)-fluoroquinolone chelates with erythrosine and their applications

In pH 4.2-5.0 Britton-Robinson buffer solution medium, fluoroquinolone antibiotics (FLQs), such as ciprofloxacin (CIP), norfloxacin (NOR), ofloxacin (OF), levofloxacin (LEV), lomefloxacin (LOM), and sparfloxacin (SPA), react with Cu (II) to form chelate cations, which further bind with erythrosine to form the ion association complexes. They can result in the changes of the absorption spectra. Simultane- ously, erythrosine fades obviously and the maximum fading wavelength is located at 526 nm. The fad- ing reactions have high sensitivities. Thus, new spectrophotometries of determination for these drugs are developed. The ion-association reactions result in the quenching of fluorescence, which also have high sensitivities. The detection limits for six antibiotics are in the range of 7.1-12.2 μg·L?1. Furthermore, the reactions can result in the enhancement of resonance Rayleigh scattering (RRS). The maximum scattering peaks of six ion-association complexes are located at 566 nm, and there are two small RRS peaks at 333 nm and 287 nm. The detection limits for fluoroquinolone antibiotics are in the range of 1.70 -3.10 μg·L?1 for RRS method. Among the above three methods, the RRS method has the highest sen- sitivity. In this work, we investigated the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reactions, and the properties of the analytical chemistry. In addi- tion, the mechanism of reactions were discussed by density function theory (DFT) and AM1 methods.

Resonance Rayleigh scattering study of the interaction of bleomycinA_5 with nucleic acids and its analytical application

The interaction of bleomycinA5 with nucleic acids has been investigated byusing resonance Rayleigh scattering (RRS),molecular absorption and fluorescence spectra.The resultshows that in near pH 2.2 buffer medium and absence of any metal ions,nucleic acids are capable ofbinding with bleomycinA5 (BLMA5) to form complexes which can remarkably enhance the RRS intensityand result in batho-chromic and hyperchromic molecular absorption of nucleic acids and fluorescencequenching of bleomycinA5.The RRS spectral characteristics for the binding products of bleomycinA5with various DNA and RNA are similar,and the maximum RRS peaks are at 301 nm for ctDNA and sDNA,370nm for hsDNA,310 nm for RNAtypeVI and RNAtypelll,respectively.The increments of RRS intensity aregreatly different in which DNA enhances greatly and RNA enhances lightly.In this work,the optimumconditions of the interaction and some influencing factors have been investigated.The reactionmechanism and a binding model for the interaction of BLMA5 with the nucleic acids are discussed.Inaddition,a highly sensitive,simple and rapid new method for the determination of DNA has beendeveloped.The detection limits (3 sigma) are 5.7 ng/mL for ctDNA,7.4 ng/mL for sDNA and 9.2 ng/mLfor hsDNA,respectively.The method can be applied to determination of trace amounts of DNA.

Special characteristics of fluorescence and resonance Rayleigh scattering for cadmium telluride nanocrystal aqueous solution and its interactions with aminoglycoside antibiotics

CdTe nanocrystals(CdTe NCs) were achieved by reaction of CdCl2 with KHTe solution and were capped with sodium mercaptoacetate.The product was detected by transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM),energy dispersive spectroscopy(EDS),fluorescence spectra,ultraviolet-visible spectra and X-ray diffraction(XRD).The CdTe NCs are of cubic structure and the average size is about 5 nm.The fluorescence quantum yield of CdTe NCs aqueous solution increased from 37% to 97% after 20 d under room light.The maximum λem of fluorescence changed from 543 nm to 510 nm and the blue shift was 33 nm.CdTe NCs aqueous solution can be steady for at least 10 months at 4℃ in a refrigerator.The resonance Rayleigh scattering(RRS) of CdTe NCs in the aqueous solution was investigated.The maximum scattering peak was located at about 554 nm.The interactions of CdTe NCs with amikacin sulfate(AS) and micronomicin sulfate(MS) were investigated respectively.The effects of AS and MS on fluorescence and RRS of CdTe NCs were analyzed.It was found that AS and MS quenched the photoluminescence of CdTe NCs and enhanced RRS of CdTe NCs.Under optimum conditions,there are linear relationships between quenching intensity(F0-F),intensity of RRS(I-I0) and concentration of AS and MS.The detection limits(3б) of AS and MS are respectively 3.4 ng·mL-1 and 2.6 ng·mL-1 by the fluorescence quenching method,and 15.2 ng·mL-1 and 14.0 ng·mL-1 by the RRS method.The methods have high sensitivity,thus CdTe NCs may be used as fluorescence probes and RRS probes for the detection of aminoglycoside antibiotics.

Absorption, fluorescence and resonance Rayleigh scattering spectral characteristics of interaction of gold nanoparticle with safranine T

The interaction between gold nanoparticle and safranine T (ST) has been studied with resonance Rayleigh scattering (RRS) spectra, absorption and fluorescence spectra. In the pH 5 solution, citrate [(H2L)2?] self-assembles on the surface of positively-charged gold nanopar-ticle, which results in the [(Au)n(H2L)m]x? complex. In other words, one of carboxylate oxygens in (H2L)2? moves inward and combines with gold nanoparticle. The other carboxylate oxygens moves outward to form a supermolecular complex anion with x negative charges. Then by virtue of electrostatic attraction, hydrophobic force and charge transfer action, the complex anion binds with ST cation to form a new ion-association complex. Here (H2L)2? acts as a bridge. The forma-tion of the complex results in the significant enhancement of RRS intensity, the appearance of new RRS spectrum, the red shift of plasma absorption band of gold nanoparticle as well as the decrease in the absorbance and fluorescence quenching for safranine T. In this work, the inter-action between gold nanoparticle and ST on the RRS, absorption and fluorescence spectra has been investigated. The reason why RRS intensity increases greatly and the reaction mechanism have been inquired. The results show that RRS spectra can not only be used to study nanopar-ticle and reaction product, but also are a sensitive means to characterize and detect nanoparti-cles.

Determination of Potassium Ferrocyanide in Foods by Resonance Rayleigh Scattering Method with Double-Charged Triaminotriphenylmethane Dyes

In pH 1.0 acidic medium, double-charged triaminotriphenylmethane dyes such as methyl green （MEG） and iodine green （IG） react with potassium ferrocyanide to form 2 ： 1 ion-association complexes by virtue of electrostatic forces and hydrophobic interaction. It results in the change of absorption and the great enhancement of resonance Rayleigh scattering （RRS） and the appearance of new RRS spectra. Two systems have similar spectral characteristics and their maximum RRS wavelengths are all located at 276 nm and smaller peaks are located at 332 and 457 nm, respectively. The intensity of RRS is directly proportional to the concentration of [Fe（CN）6]^4- in the range of 0.03-5.7 μg·mL^-1 （MeG system） or 0.04-5.9 μg·mL^-1 （IG system）. The RRS method has high sensitivity and the detection limit （3σ） for potassium ferrocyanide is 9.3 ng·mL^-1 （MeG system） or 11.2 ng·mL^-1 （IG system）. The optimum conditions, influencing factors and effects of foreign substances are investigated. The method also has a good selectivity. A sensitive, rapid and simple RRS method for the determination of potassium ferrocyanide in salinized food and table salt has been developed.

Study on the resonance Rayleigh scattering spectra and resonance non-linear spectra of congo red-amikacin system and its analytical application

The interaction between congo red (CR) and amikacin (AMK) was studied by resonance Rayleigh scattering (RRS), frequency doubling scattering (FDS) and second-order scattering (SOS) combining with absorption spectrum. In a weak acidic medium, CR combined with AMK to form an ion association complex with the composition ratio of 1∶1 by electrostatic interaction, hydrophobicity and charge transferring effect. As a result, the new spectra of RRS, FDS, and SOS appeared and their intensities were enhanced greatly. The maximum wavelengths of RRS, FDS and SOS were located at 563 nm, 475 nm and 940 nm, and the scattering intensities were proportional to the concentration of AMK. These three methods have very high sensitivities, and the detection limits were 4.0 ng·mL?1 for RRS, 3.6 ng·mL?1 for FDS and 1.9 ng·mL?1 for SOS, respectively. At the same time, the methods have better selectivity. A new method for the determination of trace amounts of AMK with congo red by resonance scattering technique has been developed. The recovery for the determination of AMK in blood serum and urine sample was between 95.5% and 105.5%. In this study, the properties, such as enthalpy of formation, charge distribution and mean polarizability, were calculated by AM1 quantum chemistry method. In addition, the reaction mechanism and the reasons for the enhancement of scattering spectra were discussed.

The interaction between furosemide-palladium (Ⅱ) chelate and basic triphenylmethane dyes by resonance Rayleigh scattering spectra and resonance non-linear scattering spectra and their analytical applications

In pH 4.5-7.0 Britton-Robinson buffer solution,furosemide (FUR) reacted with Pd (II) to form a 1:1 anionic chelate.This chelate could further react with such basic triphenylmethane dyes (BTPMD) as ethyl violet (EV),crystal violet (CV),methyl violet (MV),methyl green (MeG) and brilliant green (BG) to form 1:1 ion-association complexes.This not only resulted in the change of absorption spectra,but also led to the significant enhancement of resonance Rayleigh scattering (RRS),second-order scattering (SOS) and frequency doubling scattering (FDS).The maximum RRS wavelengths were located at 324 nm for the EV,CV and MV system,and 340 nm for the BG and MeG system.The maximum SOS wavelengths were located at 550 nm for the EV,CV,BG and MeG system,and 530 nm for the MV system.The maximum scattering peaks of all the systems were at 392 nm for FDS.The enhanced RRS,SOS and FDS intensities were directly proportional to the concentration of FUR.The detection limits for the different dye systems were 0.3-4.9 ng mL-1 for the RRS method,3.2-33.1 ng mL-1 for the SOS method and 9.0-85.7 ng mL-1 for the FDS method.These methods could be used for the determination of trace amounts of FUR.The effects of the formation of ternary ion-association complexes on the spectral characteristics and intensities of absorption,RRS,SOS and FDS have been investigated.The optimum conditions of these reactions,the influencing factors and the analytical properties have been tested.The influences of coexisting substances were tested by RRS method and the results showed that this method exhibited a high sensitivity.Based on the aforementioned research,the highly sensitive,simple and rapid methods for the determination of trace amounts of FUR by resonance light scattering technique have been established,which could be applied to the determination of FUR in tablet,injection,human serum and urine samples.The composition and structure of the ternary ion-association complex and the reaction mechanism were discussed.

Resonance Rayleigh scattering spectrum for the chelate of lanthanum(Ⅲ) with sodium tanshinon ⅡA silate and its analytical application

In a pH 3.6―5.0 HAc-NaAc buffer solution, when sodium tanshinon ⅡA silate (STSⅡA) reacts with La(Ⅲ) to form a chelate, the resonance Rayleigh scattering (RRS) intensity can be en-hanced greatly and a new RRS spectrum will appear. The maximum RRS peak is located at 306 nm and the RRS intensity is proportional to the concentration of STSⅡA in a certain range. The method is very sensitive and the detection limit for STSⅡA (3σ/K) is 82.12 ng·mL?1. The optimum reaction condi-tions and the effect of coexisting substances have been investigated. A new, simple and fast method for the determination of STSⅡA based on RRS method is developed. It can be applied to the deter-mination of STSⅡA in the synthesis samples and Nuoxinkang injection. Combined with infrared ab-sorption and NMR spectra, the structure of the chelate and the reasons of RRS enhancement are also discussed.

Binding equilibrium of I^- to serum albumin with resonance Rayleigh scattering

The binding equilibrium between l? and human serum albumin (HSA) or bovine serum albumin (BSA) has been studied by means of the resonance Rayleigh scattering (RRS) and equilibrium dialysis. It has been found for the first time that RRS and multiple frequency scattering (MFS) are enhanced as the l? binding to the HSA and BSA, but fluorescence quenches. The equilibrium dialysis results suggest that the binding of l? to HSA and BSA fits a phase-distribution model other than Scatchard model, and that the order of magnitude of its phase-distribution constant was found to be 104. It is most probable that Cl? or other anion ions influence the binding of l? by changing the ionic strength in the solution. The dialysis at different pH indicates that the binding mechanism is due to the electrostatic forces between the l? and protonated basic amino-acid residues.

The resonance Rayleigh scattering of the interaction of copper(Ⅱ)-bleomycinA2 with DNA and its analytical application

The forming of bleomycinA2-Cu(Ⅱ) cationic chelate and the interaction of the chelate with DNA have been investigated by using resonance Rayleigh scattering(RRS),molecular absorption and fluorescence spectra.The result shows that in aqueous solution,bleomycinA2(BLMA2) can react with Cu(Ⅱ) to form 1:1 cationic chelate which contributes to the changes of the absorption spectra and the quenched fluorescence of BLMA2.When the cationic chelate further bound with DNA to form ternary ion-association complexes,the remarkable enhancement of the RRS intensity was observed.In this work,the optimum conditions for the coordination reaction of BLMA2 with Cu(Ⅱ) and some influencing factors have been investigated.The reaction mechanism of BLMA2-Cu(Ⅱ) binding with DNA was suggested and a binding model was proposed.In addition,the fluorescence quenching type of BLMA2 was investigated.A highly sensitive,simple and rapid new method for the determination of DNA by using BLMA2-Cu(Ⅱ) as RRS probe has been developed.The detection limits(3σ) are 7.2 ng/mL for ctDNA,7.1 ng/mL for sDNA and 18 ng/mL for hsDNA.The method can be applied to the determination of trace amounts of DNA.

Absorption, Fluorescence and Resonance Rayleigh Scattering Spectra of Interaction of Papain with Calf Thymus DNA

In weak acidic medium, interaction between papain and calf thymus DNA （ctDNA） resulted in absorption spectral change, fluorescence quenching of papain and remarkable enhancement of resonance Rayleigh scattering （RRS） The interaction types and binding modes were discussed by characteristics of RRS, absorption, fluorescence and circular dichroism spectra combining thermodynamic data. Four interaction types include electrostatic attraction, hydrophobic force, hydrogen bonding and aromatic stacking interaction. Papain interacted with the major groove of ctDNA. Aromatic stacking interaction is the main reason of change of absorption spectrum and fluorescence quenching of papain. Surface enhanced scattering effect, resonance energy transfer effect, increase of molecular volume and conformational change make contribution to RRS enhancement. The enhanced RRS intensity （△I） is directly proportional to the concentration of ctDNA or papain, The detection limit （3σ） is 5.2 ng·omL^-1 for ctDNA and 5.6 ng·mL-1 for papain. This creates conditions for determination of papain and ctDNA.