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| Content Provider | World Health Organization (WHO)-Global Index Medicus |
|---|---|
| Author | Jia, Guiying Wan, Qian-Hong |
| Description | Country affiliation: China Author Affiliation: Jia G ( School of Pharmaceutical Science & Technology, Tianjin University, 92 Weijin Road, Tianjin 900032, China.); Wan QH ( School of Pharmaceutical Science & Technology, Tianjin University, 92 Weijin Road, Tianjin 900032, China. Electronic address: qhwan@tju.edu.cn.) |
| Abstract | A high-performance liquid chromatography with online electrospray ionization mass spectrometry (HPLC-ESI-MS) has been used to separate and identify the reaction products resulting from controlled acid-catalyzed hydrolytic polycondensation of vinyltrimethoxysilane (VMS). The reaction products were prepared in the molar ratio of water to VMS (r1) ranging from 0.6 to 1.2, characterized by standard spectroscopic techniques, and subsequently analyzed by HPLC-UV absorbance detection and HPLC-ESI-MS. Linear vinylmethoxysiloxane oligomers with the number of repeat units (n) ranging from 3 to 11 are predominant species at the beginning of the reaction (for r1=0.6). Then they transform into monocyclic (for r1=1.0) and bicyclic (for r1=1.2) species with gradually increasing amount of water in the reaction mixture. The oligomer conversions suggest that structure growth of vinylmetoxysiloxanes proceeds by nonrandom cyclization reactions, which are favored over chain extension under the chosen reaction conditions. Direct ESI-MS, HPLC-ESI-MS and HPLC-UV were used to determine the molar mass distributions for the vinylmethoxysiloxane oligomers prepared in three different values of r1. The molar mass averages increase slightly with the amount of water in the reaction mixture and vary somewhat with the method used. Our results indicate that with the combined capability of separation, sensitivity and identification, HPLC-ESI-MS is especially useful to study highly complex silicon-based compounds with hyperbranched, caged or cubic structures as building blocks for hybrid materials. |
| ISSN | 00219673 |
| Journal | Journal of Chromatography A |
| Volume Number | 1395 |
| e-ISSN | 18733778 |
| Language | English |
| Publisher | Elsevier |
| Publisher Date | 2015-05-22 |
| Publisher Place | Netherlands |
| Access Restriction | One Nation One Subscription (ONOS) |
| Subject Keyword | Chemistry Techniques, Analytical Methods Chromatography, High Pressure Liquid Siloxanes Analysis Chemistry Spectrometry, Mass, Electrospray Ionization Molecular Weight Journal Article Discipline Analytical Chemistry |
| Content Type | Text |
| Resource Type | Article |
| Subject | Organic Chemistry Medicine Analytical Chemistry Biochemistry |
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