Applications Of Spectroscopic Methods In Protein And Pharmaceutical Analysis

In this paper, we investigated the applications of resonance light scattering and fluorescence spectrum methods in the field of biochemistry research as follows:Firstly, the formation of Au nanoparticles (Au NPs) as a result of the thermo-active redox reaction of chlorauric acid (HAuCI4) and glucose in alkaline medium was identified by measuring resonance light scattering (RLS) signals, transmission electron microscopy (TEM) images and their absorption bands. It was found that the resulted RLS signals could be easily detected with a common spectrofluorometer. With increasing glucose concentrations, the RLS intensity displays linear response with the glucose content over the range from 2.0 to 250.0μmol/L. Thus, a novel assay of glucose was established with the limits of determination (3σ) being 0.21μtmol/L, and the detection of glucose could be made easily in the serum samples of diabetes sufferers. Mechanism investigations showed that the activation energy and molar ratio of the reaction were 34.8 kJ mol and 3: 2, respectively.Furthermore, we found that tryptophan can react with HAuCl₄ also, and product Au Nanoparticles, we chose more than 10 kinds of familiar amino acids, and only tryptophan can react with HAuCl₄ in the condition of pH 1.98, accordingly, we established a new method of tryptophan assay, and its linear range is 0.21-60.1 mmol/L, limit of detection is 21.3μmol/L.A rapid and sensitive method for the determination of proteins is proposed based on enhanced resonance light scattering signals by a new Schiff base dye, which was synthesized by O-phthalaldehyde and sulfanilic acid. On the acidic condition, the interaction between the Schiff base dye and proteins occurs rapidly, resulting in greatly enhanced resonance light scattering signals with the maximum peak located at 344.0 nm. Based on the linear relationship between enhanced resonance light scattering resonance light scatteringintensitues and proteins concentrations, a novel assay for HSA and BSA is established with the limits of detection (3σ) being 0.09×10^-4 mol/L and 25.0×10^-4 mol/L respectively. As results of our research were consistent with the documented spectrophotometric (CBB G250 assay) method, we believe that the protein content of the serum samples can be successfully detected by the developed method.A novel fluorescent assay for captopril based on the chemical reaction between captopril and O-phthaladehyde in the presence of isoleucine was proposed in this paper. The resulted isoindole group displays characterized fluorescence signals at 452.0 nm with the excitation of 340.0 nm, and such enhanced fluorescence emission is linear with captopril concentrations over the range of 5.0-1000.0 nmol/L, while the limit of detection is 0.68 nmol/L. The proposed procedure was successfully applied to the determination of captopril in its tablets with recoveries of 90.5-96.8%, and human urine samples with recoveries of 95.3-104.9%.