Applications Of Light Scattering Technique In The Pharmaceuticals And Biomacromolecules

Since the establishment of the light scattering technique, it has applied widely and developed quickly. In this contribution, based on the resonance light scattering (RLS) technique, we have employed the plasmon resonance light scattering (PRLS) properties of metal nanoparticles and constructed methods for the determination of the Pharmaceuticals and biomacromolecules, which would provide sensitive detection methods for pharmaceuticals and biomacromolecules and may be helpful in the fields of medicine and biochemistry; Raman scattering and Inner Filter Effect (IFE) are the interference sources in spectrofluorometry, we have coupled them together reasonably and proposed a novel approach for the determination of Co(II) by spectrofluorometer, the function of spectrofluorometer can be further exploited; Poor selectivity is always the factor that limits the development of RLS technique, to solve the problem, we have also incorporated the high performance liquid chromatography (HPLC) technique and the RLS technique by employing the insulin as a model system, We hope that the combination of HPLC-RLS technique could improve the selectivity and stability of the RLS technique and then develop a new technique with high slectivity and high sensitivity. The main contents of investigation in the contribution are as follows:Metal nanoparticles have been found the applications in the fields of pharmaceuticals and biomacromolecules analysis for their unusual physicochemical properties. Of the nanoparticles, especially gold and silver nanoparticles, their plasmon absorption properties have been widely used in the fields, such as DNA hybridization, immunoassay and so on, but the research on their PRLS properties has been little reported. In this contribution, we have focused on the PRLS properties of the nanoparticles and applied them to the pharmaceutical and biomacromolecules analysis.1). In the coexistence of NaOH and NH₃-H₂O medium, it was found that, Ferulic Acid (FA) acts as a reducing agent and can be oxidized by AgNO₃, resulting in the formation of silver nanoparticles (NPs) which give the enhanced PRLS signals, the detection method of FA was constructed according to the linear relationship between the PRLS intensities and the concentrations of FA. Under the optimal conditions, the FA concentrations of 0.2².0umol L^-1 could be detected and the detection limit was 15.2nmol L^-1. The results have shown that the method is simple, rapid and sensitive, it also provides a reliable detection method for other phenolic compounds. What's more, the present reaction maybe provides the basis of an environmentally friendly approach for the synthesization of silver nanoparticles.2). In the alkaline medium with the coexistence of NaOH and NH₃H₂O, one of the Catecholamines, L-DOPA can be oxidized by AgNO₃, resulting in the formation of silver NPs and the enhanced PRLS signals, the method for L-DOPA detection was constructed according to the linear relationship between the PRLS intensities and the concentrations of L-DOPA. Under the optimal conditions, the L-DOPA concentrations of 0.2～2.0μmolL^-1 could be detected and the detection limit was 20.1nmol L^-1. By the mechanism investigations, we conclude that the groups oxidized in L-DOPA are the two adjacent phenol groups, while all the catecholamine compounds possess the two adjacent phenol groups, so all of other catecholamine compounds, such as dopamine, adrenaline, noradrenaline, could be anticipated to be oxidized by AgNO₃ under the corresponding conditions, resulting in the formation of silver NPs and the enhanced PRLS signal, so the detection methods for the catecholamine compounds could be constructed as L-DOPA. The results of detection L-DOPA have shown that the method is simple, rapid, sensitive and reliable.3).Thrombin plays an important role in the course of thrombus formation, so the detection of thrombin has important significances for the diseases diagnosis, evolution, evaluation of curative effect. In this contribution, gold nanoparticles (NPs) stabilized with citrate were functionalized by the thiolated thrombin binding aptamer (TBA), the gold NPs are served as a probe, when thrombin was added into the solution, the gold NPs would be aggregated for thrombin reacted with TBA, which was testified by the absorption spectra and the TEM images of gold NPs, and the then the PRLS signals were enhanced, so we set up a method for the detection of thrombin based on the PRLS signals of gold NPs. The results showed that the PRLS intensities were in proportion to the thrombin concentrations over the range of 1.8～9.0nmol L^-1, the detection limit of thrombin was 0.2 nmol L^-1, so it is a sensitive method for thrombin detection. During the initial phase of coagulation thrombin is produced in nanomolar concentrations, so the present method can be used for the clinical detection of thrombin.Both Raman scattering and IFE are the interference sources and usually should be avoided or corrected in spectrofluorometry. We suppose analytical sciences lie on the reasonable application of signals only if the intensity of the signals has simple functional relationship with the content of analytes. In this contribution, we propose a quantitative method based on the IFE of reagents on the Raman scattering signals of solvent by taking the complexation of Co(II) with 4-[(5-chloro-2-pyridyl)azo]-l,3-diaminobenzene (5-C1-PADAB) as a model system on a common spectrofluorometer. In a solution of 5-C1-PADAB, the Raman scattering signals of water are decreased owing to the IFE of 5-C1-PADAB, after the addition of Co(II) which can form the complex with 5-C1-PADAB and consumes the reagent, then the Raman scattering signals were found recovered, based on the linear relationship between the enhanced Raman scattering intensities and the concentrations of Co(II), Co(II) was detected, the detection limit is 1.2×10^-7 mol L^-1 which is comparable to the generally used UV-Vis spectrophotometry. In the present method, the commonly used solvent, water, serves as a probe, and the Raman scattering signals of water are used, the obtain of Raman scattering does not require flexed excitaion wavelength, so we can freely select the excitation wavelength according to the analyte, which is very flexible and simple. What's more, a novel method for detection of some non-fluorescent compounds was proposed in a common spectrofluorometer, the function of spectrofluorometer was further exploited.As we know, the RLS technique is very sensitive for the detection, but its poor selectivity and stability are the limitations for being as a perfect technique. While high separation resolution and selectivity are the advantages of chromatography all the time, the disadvantage lies in the poor detection sensitivity. Here HPLC is chosen as a model, combining the advantages of the both techniques, the incorporation of HPLC-RLS was carried out in the contribution, the incorporated technique not only improves the selectivity and stability of the RLS technique, but also enhances the detection sensitivity of HPLC and enriches the detection types of HPLC. With the deep research and developed incorporated technique, the RLS detector is hopeful for HPLC.