The Preparation Of Functional Nanoparticles And Their Applications In Colorimetric Detection And Enantioseparation

Nanoparticles, such as metal nanoparticles, mesoporous silica nanoparticles,organica polymer and so on, with at least one dimension in the range1~100nm, havebeen widely used into chromatography separation, biological and chemical detectionand analysis, due to their large specific surface area and unique electronic, optical,magnetic and mechanical properties. Surface functionalized nanoparticles withspecific features can be used in capillary electrophoresis to improve separation. Thisthesis mainly includes the following three chapters:In the first chapter, a review on the liquid chromatographic separation ofenantiomers through nanostructures was presented, as well as the recent applicationsin electrodriven enantioseparation. Metal nanoparticles applied to enantioseparationand enantiorecognition were also reviewed subsequently.In the second chapter, we reported a new, facile, one-pot robust approach for thesynthesis of well-dispersed water soluble gold nanoparticles (GNPs) by the reactionof aqueous sodium tetrachloroaurate (III)(HAuCl4) with norvancomycin (NVC), aglycopeptide antibiotic, under basic conditions without the assistance of any otherreagents. The obtained GNPs were characterized with transmission electronmicroscopy (TEM), ultraviolet–visible absorption spectroscopy (UV-vis), dynamiclight scattering (DLS), fourier transform infrared spectroscopy (FT-IR) and X-raydiffraction (XRD). The results indicated that the surfaces of GNPs were coated with arobust layer of NVC, making GNPs maintain stable for a very long time. Thus, NVCacts as both the reducing and the capping agent. Subsequent experiments showed thesize of the GNPs can be tuned by varying the reaction temperature and the pH ofreaction system, and the GNPs thus synthesized can form stable dispersion in solutionwith wide pH range and high NaCl concentration. Basing on the findings that cysteinecould induce the aggregation of colloidal solution, resulting in changes in color and inUV-vis absorption spectra, a rapid and simple GNPs-based colorimetric method forthe detection of cysteine was established.In the third chapter, diamino moiety functionalized silica nanoparticles (dASNPs)were dispersed in the running buffer solution and used as pseudo-stationary phases toenhance the enantiomeric separation in chiral capillary electrophoresis (CE) system. Two popular β-CD derivatives, namely carboxymethyl-β-cyclodextrin (CM-β-CD)and hydroxypropyl-β-cyclodextrin (HP-β-CD) were used as chiral selectorsrespectively. For both chiral selectors, obvious selectivity differences were observedbetween the buffer containing dASNPs and buffer without. However, the presence ofdASNPs increased the resolution (Rs) much more greatly when using CM-β-CD aschiral selector in comparison with that of HP-β-CD, mostly because of the strongerinteraction between CM-β-CD and dASNPs. The interaction between dASNPs andCM-β-CD was further characterized and confirmed by Zeta potential, NMR etc, andthe possible mechanism for the improvement was also discussed. It was also foundthat the presence of suitable amounts of dASNPs in buffer solution can greatlydecrease the required amount of CM-β-CD by1~2orders of magnitude.