| Summary: | 碩士 === 中原大學 === 化學研究所 === 100 === In this study, the monolithic columns were used for the capillary electrochromatographic (CEC) separation of basic compounds. CEC method coupled either with UV or mass spectrometric detection was developed for the detection of melamine and its derivatives (ammeline, ammelide, and cyanuric acid). A series of poly(alkene-divinylbenzene-VBTA) monolithic columns, such as 1-octene, 1-dodecene or 1-octadecene, were used as separation columns with vinylbenzyl trimethylammonium chloride (VBTA) as the positive charged monomer and EOF provider. Optimization of the polymerization conditions (monomer level and ratio of charge-monomer) and mobile phase conditions (ACN content, pH value and concentration of electrolyte) were conducted.
The poly(1-dodecene-DVB-VBTA) monolith was chosen as the optimal chromatographic material because it provided a better separation of the four melamine derivatives, which was completed within 5 min. Detection limit was in the range of 0.6-2.18 mg L−1 by the optimal CEC-UV mode, and was reduced from 2.2 to 19.4μg L−1 by the optimal CEC-MS mode. Finally, the proposed CEC methods successfully determined melamine contaminations (0.1 mg L−1 per analyte) in milk powder with analyte recovery range of up to 70%, with even better detection ability than previous GC–MS, CE–MS, as well as LC–MS methods.
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