| Flavonoids is a kind of polyphenols widely distrbuted in nature with wide rangeof biological activities and pharmacological activity. A large number of studies haveshown that flavonoids scavenge free radicals, anti-oxidation, anti-tumor, preventionand treatment hardening of the arteries, reducing blood suger and other functions.Because of characteristics of pure natural, high activity and wide rang, flavonoids aregradually noticed by people. Flavonoids spread widely in plant kingdoms and theexisting analysis methods of which are multiple steps and time-consuming. It isunfavorable to the further development of the flavonoids. Therefore, developing arapid and high sensitivity analytical method is conducive to the development andutilization of flavonoids. Chemiluminescence (CL) is a kind of analysis methodswhich is applied widely and developed rapidly in recent decades. It is often applied intrace analysis due to its high sensitivity, simplicity, and low cost. However, the studyof CL was limited to molecular and ion systems. Recently, metalnanoparticle-involved CL have higher sensitivity, in which metal nanoparticles canparticipate in CL reactions as catalyst, reductant and so on. Metalnanoparticle-catalyzed CL was applied to the determination of flavonoids due tocharacteristics of fast and low detection limit, which could satisfy with therequirement of analysis. Therefore, according to the characteristics of the flavonoids,we design a new CL analysis method, which is a new idea to research flavonoids. Inaddition, it is also a kind of important idea to find the new application of existingsystems by the in-depth study of the mechanism. In this thesis, we select the flavonoidas the target and design a new CL analysis method which use off-line gold nanoparticle-catalyzed chemiluminescence system. At the same time, the classicoff-line, on-line gold nanoparticle-catalyzed CL system are applied to analyseflavonoids which broaden the scope of practical application of these CL system. Theresearch work was illustrated in detailed as follows:It was found that gold nanoparticles (AuNPs) could remarkable enhance thechemiluminescence (CL) intensity of luminol–HgCl2system. On the basis ofenhancement effect, a rapid and easy flow injection–chemiluminescence method hasbeen established for the determination of luteolin. At the same time, various factorswhich influenced the chemiluminescence system were investigated carefully. Thepossible mechanism of the proposed method was also studied. The results show thatthe optimal comditions of chemiluminescence system are0.1mol/L NaOH，4.0×104mol/L luminol，6.08×105mol/L AuNPs and1.0×103mol/L HgCl2. Under the selectedexperimental conditions, the linear range was2.0×109~1.0×107g/mL(r=0.9929)andthe detection limit was1.5×109g/mL. The relative standard deviation (RSD) was2.1%for1.0×10-8g/mL luteolin (n=11). The method was successfully applied to thedetermination of luteolin in serum and synthetic samples and the average recoverywere100.8%and99.5%respectively. It was found that flavonoids could remarkable inhibit the chemiluminescence(CL) intensity of off-line gold nanoparticle-catalyzed luminol–hydrogen peroxide CLsystem. To the contrary, flavonoids could enhance CL intensity of on-line goldnanoparticle-catalyzed luminol–hydrogen peroxide CL system. At the same time, theinhibitory effects and enhancing activity of12flavonoids were different. Then thedifferences are researched by UV-visible absorption spectra and flow injectionchemiluminescence. The results show that differences signal suppression effect offlavonoids on off-line gold nanoparticle-catalyzed CL system are influenced by thecombined action of free radical scavenging effect and occupy-sites function. Sinceflavonoids can reduce chloroauric acid to produce gold nanoparticles which cancatalyze CL system and form enhancement effects on signal of CL. This workbroadens the scope of practical application of gold nanoparticle-catalyzed CL system.In addition, lots of flavonoids can be rapid analyzed by take advantage of the specialcelerity and sensitivity in the future. |
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