Qualitative Or Quantitative Study On The Action Of Coumarin And Ciprofloxacin By SERS Technique

Raman spectra?Raman spectra?got its name because it was discovered by Indian scientist Raman and other researchers.Raman spectroscopy is an inelastic scattering,which can obtain information about molecular vibration or rotation,and can be used as a method to study molecular structure.However,Raman spectroscopy still has a lot of limitations in practical applications.This is mainly because the Raman effect is weak first,and secondly,the test conditions for the sample are harsh.Surface-enhanced Raman Spectroscopy?SERS?refers to the detection of molecules attached to rough metal surfaces such as silver,gold,copper,etc.?usually precious metals?,which can produce corresponding enhancement effects,the degree of enhancement is as high as conventional 10⁵-10⁸ times the Mann signal.Surface-enhanced Raman spectroscopy is widely used in many fields such as medicine,pharmacy,environmental testing,food testing,etc.This is mainly due to its own advantages.The first is that SERS technology reduces the requirements for samples,and the second is because SERS detection is not disturbed by Raman peaks in solvent water,but also makes up for the shortcomings of low sensitivity of conventional Raman spectroscopy.In addition,surface enhanced Raman spectroscopy has the advantages of short analysis time and non-destructive testing of samples.In view of the analytical advantages of the SERS technology,this paper mainly uses the SERS technology to qualitatively or quantitatively study the action characteristics of coumarin and ciprofloxacin.Using silver nanoparticles as a substrate,the role of coumarin and protein was investigated,which provided new ideas for the subsequent study of the interaction between multiple flavoring agents and proteins.At the same time,using SERS technology to quantitatively detect the coumarin content in actual samples,combined with the L₉?3⁴?orthogonal design experiment,determine the optimal conditions for detecting coumarin,and provide a reference for the cosmetics industry to detect illegal additives.Finally,using gold nanoparticles as the substrate,SERS technology was used to qualitatively study ciprofloxacin and explore the role of ciprofloxacin and aminophylline,which is necessary for the clinical use of mixed drugs.The main content of this paper is the following four parts:?1?This article briefly introduces the development history,background,basic principles,and related characteristics of Raman spectroscopy and surface-enhanced Raman spectroscopy,as well as the research progress of the application of SERS technology in various fields in recent years.?2?Using silver nanoparticles as the substrate,the coumarin was subjected to conventional Raman test and surface-enhanced Raman spectroscopy test.The results showed that the silver nano-substrate had a good Raman enhancement effect and was attributed to coumarin Raman At the same time,the mixing volume ratio of bovine serum albumin?BSA?and silver nanoparticles was optimized.The results showed that when the volume ratio of the two was 1:3,the Raman enhanced signal of BSA was the best.The effect of coumarin solution and BSA was experimentally studied.After the coumarin solution was mixed with BSA,a Raman test was performed on the mixed solution.The results showed that the addition of BSA resulted in multiple Raman coumarins.The red shift of the displacement occurs mainly at 525 cm^-1,675 cm^-1and 1327 cm^-1of coumarin.The asymmetric stretching vibration of C-O and the stretching vibration of C=O of coumarin also cause multiple Raman shifts.Changes,such as the drop in Raman signal at 1184 cm^-1,1230 cm^-1,1327 cm^-1,and 1563 cm^-1;the disappearance of Raman peaks at 847 cm^-1,897 cm^-1,and 1488 cm^-1;The legume vibrations were also affected.Compared with coumarin SERS,after adding BSA and mixing,the SERS signal of coumarin was obviously weakened at this time.It is likely that the planar structure of the coumarin molecule was inserted into the?-helical structure of BSA.The accumulation of?-?non-covalent bonds causes the?electron density of the aromatic ring in coumarin to change,which further causes the energy to change.This fast and convenient analysis method provides a reference for in-depth research on the interaction between other flavoring agents and proteins,and is worthy of promotion in other fields.?3?SERS technology was combined with L₉?3⁴?orthogonal design experiment to quantitatively detect coumarin in cosmetics.In this experiment,by analyzing the SERS diagram of the coumarin standard solution,the basis for quantitative calculation of coumarin was determined,and the stability and selectivity of this characteristic peak were discussed.The detection conditions of coumarin were optimized to determine the best detection conditions for coumarin.Under the optimal experimental conditions,a standard curve of the mass concentration of Raman peak at 663 cm^-11 was established.The results show that the SERS method has a good linear response in the detection of coumarin in the range of 0.1 to100 mg/L mass concentration.The linear equation is Y=0.0036c+0.5411,where Y=measured Raman intensity?a.u.?/10⁵,the correlation coefficient R² is 0.99,and the detection limit is lower than 0.2 mg/L.This method has high sensitivity and good accuracy.In view of this,this method is used for the detection of coumarin in loose powder,lipstick and lipstick.?4?The Raman peak of Ciprofloxacin?CIP?was calculated based on the B3LYP/6-31G?d,p?basis set of Density function theory?DFT?,and the SERS of ciprofloxacin solution was measured.As a result,it was found that the Raman peak of ciprofloxacin solution had better enhancement effect with gold nanoparticles as the active substrate.In this experiment,the Raman peak of ciprofloxacin was comprehensively assigned.SERS technology was used to study the interaction between ciprofloxacin and aminophylline,and the effect of binding time on the mixture of aminophylline and ciprofloxacin was investigated.The results show that with the extension of the binding time,the force between the two strengthens,and some Raman peaks of ciprofloxacin disappear.And with the continuous increase of the amount of aminophylline,the molecular structure of ciprofloxacin is greatly affected,its Raman signal is weakened,and many Raman peaks are changed,mainly the pyrazine ring at 1184 cm^-1,The C-F at 1252 cm^-1,C=C at 1627 cm^-1,and O-C-O at 1458 cm^-11 have changed the vibration frequency;the more the aminophylline content increases,the more it affects the structure of ciprofloxacin.Seriously,when the amount of aminophylline exceeds 22.5 mg/L,except for a weak signal at 1384 cm^-1,almost no other peaks appear.This experiment uses SERS technology to investigate the interaction between aminophylline and ciprofloxacin,which provides a reference for its pharmacological research.