Applications Of Light Scattering Technique In Analysis Of Food Security And Biochemical Medicament

RLS technique attracted attention and developed rapidly due to high sensitivity, simple manipulation and convenient experimental conditions. Now, RLS has been a strong and effective technique in analyticle chemistry. In this paper, we qualitatively and quantitatively detect environmental heavy metal ion Ag⁺ and carcinogen Sudan in food production with plasmon resonance light scattering (PRLS) signals, determine biochemical drug heparin, and study the selective identification of T base by Co(â…¡) and 5-Cl-PADAB, and analyse the positive effect of carbon nanotube (CNT), which can provide useful information in theory and experiment research of applications in clinical diagnosis, environment science, food industry, etc. The main content is as follows:(1) A novel method of detecting Sudan based on the formation of silver nanoparticles (NPs) in food products is reported. Sudanâ… ,â…¡,â…¢andâ…£have reducibility due to the functional groups of nitrogen-nitrogen double bond and hydroxide, and oxidation- reduction (Ox-Red) reaction could occur using AgNO₃, forming silver nanoparticles. Color changes of Sudan could be observed from red to brown during the Ox-Red reactions, resulting in greatly plasmon resonance light scattering (PRLS) signals characterized at 452 nm. The PRLS intensities are in proportion to the concentrations over the range of 0.2-2.4μmol/L Sudanâ… , 0.1-2.4μmol/L Sudanâ…¡, 0.1-2.4μmol/L Sudanâ…¢and 0.2-3.0μmol/L Sudanâ…£, with the corresponding limits of determination (3σ) of 3.2 nmol/L, 3.0 nmol/L, 3.2 nmol/L and 2.9 nmol/L, respectively. Using hot chili as a model example, detections could be made with the recovery of 90.8-103.3% and RSD of 4.0-4.9%, and the results are identical with that of HPLC. Mechanism investigations show that the functional group of Sudan oxidized by AgNO₃ is the hydroxide, not the functional groups of nitrogen-nitrogen double bond.(2) Heparin is a kind of amylose, and the main medical functions are anti-cruor, restraining blood platelet, controlling blood wessel rebirth, regulating blood grease, anti-inflammation, antihypersusceptibility, etc. Under the basic condition of 0.042 mol/L NaOH, Co(â…¡) and 5-C1-PADAB can combine to produce a Coordination compond with positive charge, which could be combined by heparin with negative charge via electrostatic process, resulting in enhanced resonance light scattering (RLS) signals characterized at 550 nm. RLS intensity is in proportion to the concentrations of heparin. Thus, a method to detect heparin is constructed.(3) Working solutions of A₆, G₆,C₆,T₆were repectively added into the complex of Co(â…¡) and 5-Cl-PADAB under basic condition. It shows that RLS changes are different. RLS intensities nearly remain the same when A₆,G₆,C₆ were added, while, enhanced obviously by T₆, and enhanced more obviously when MWNTs dispersed solution is added. Thus, we can deduce that DNA and the complex combine via T base, which is important for gene diagnose and analysis.