Nanomaterial-Based Mass Spectrometry for Analysis of Ultraviolet Absorbers in Urine and the Charge-State Distribution of Protein
| Autor: | Tzung-Jie Yang, 楊宗杰 |
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| Rok vydání: | 2011 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 99 In this thesis, nanomaterial-based electrospray mass spectrometric approach was utilized for small molecular and macromolecular analysis. The thesis is divided in five chapters. The functionalized magnetic nanoparticles, Fe3O4/SiO2 was synthesized and then utilized for analysis of eleven ultraviolet absorbers in urine. The feasibility of the presented method was also evaluated. The linear range of proposed method were 10-1000 ng mL-1 for HBP, BP-3, BP-2, BP-6 and 4-MBC; 0.5-1000 ng mL-1, 0.5-500 ng L-1, 0.75-1000 ng mL-1 and 0.75-500 ng mL-1 for DHB, BP-12, DHMB and OD-PABA, respectively. LODs were ranged from 0.1 ng mL-1 to 8.8 ng mL-1 with R.S.D. below 10.8%. This approach was also applied for real samples analysis. The trace amount of DHMB in urine was detected and the concentration is 277.1 ng mL-1. The ambient mass spectrometry for one-droplet analysis was developed in this thesis. A 3.5 μL solution was dipped on a laboratory-made screen-printed plate coated with silver or graphite gel. The voltage of +5 kV was applied on the surface of the droplet and electrospray was performed when applying the voltage. The ultraviolet absorbers studied are including 3-(4-methylbenzylidene)-camphor (4-MBC), 2-ethyl-4-(dimethylamino)benzoate (OD-PABA) and 2-hydroxy-4-(octyloxy)-benzophenone (BP-12). To evaluate the effect on the ionization efficiency, the solution containing analytes and nanomaterials was dipped on the screen-printed substrate. From the results, the MWCNTs can enhance the intensity of the signal detected and short the analytical time. This technique demonstrates that the nanoparticles assisted electrospray ionization offers a high specific and high throughput screening for trace analysis. The analysis of protein conformation by ESI-MS was devoted in this study. This work outlines the changes to the charge-state distribution (CSD) and to improvement of the resolution of isotopic peak when the nanomaterial solution is infused to the ion source and co-electrosprayed with the protein-contained solution. The various conformation gold nanoparticles (AuNPs) and titanium dioxide nanoparticles (TiO2) were used in this study. Generally the ESI-MS of protein solution often show a monomodal distribution of charge-state peaks with a maximum charge-state and a most-intense charge-state. When AuNPs mixed with protein such as cytochrome c and ubiquitin, the mass resolution of isotopic peak in the mass spectrum were improved. The ESI-MS of protein solution was shown the average distribution of isotopic peaks with the most-abundant charge-state. For the assessment of myoglobin with AuNPs and TiO2, the charge-stated peaks of protein were shifted. The present study was demonstrated the effect of nanomaterials on the charge-states distribution of protein and the characteristics of isotopic peaks of protein in ESI-MS. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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