Determination of Organic and Inorganic Ions by Conductometric Capillary Electrophoresis Microchip

• Main Authors: Ming-Tai Lu, 呂明泰
• Other Authors: Guan-Liang Chang
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/38876749222346211416

碩士 === 國立成功大學 === 醫學工程研究所碩博士班 === 93 === 　Conductivity detection can be considered electrochemical technique as well but has the ability to detect any analyte irrespective of whether it contains an electroactive species or not. We used MEMS (Micro electromechanical system) to fabricate the microelectrode, and its specification of width and interval are 50 �慆 and 30 �慆 individually. The microchannel was obtained by cast. After fabricating the mold, PDMS (polydimethylsiloxane) was poured into the cast and cured a period of time. Then peeled PDMS replica from mold and the microchannel was completed. It was 13 �慆 in width and 150 �慆 in depth. In the CE experiment, we detected organic components such as catechol, dopamine, histamine and vitamin C, and inorganic ions like K+, Li+ and Ca2+. The application of heavy metals, including Hg2+, Zn2+, Pb2+, Ag+ and Cu2+, was also investigated. 30 sec electrokinetic injection time for individual sample detection was performed using a field strength (E) of 440 V/cm, and E = 230 V/cm for electrophoresis. Each sample can be detected less than 90 sec excluding catechol. Limitation of detection (LOD) is different from each other. The lowest LOD is 25 �嵱 (5 ppm) for Hg2+. On the other hand, the electrophoresis conditions of mixed analytes were 80 V/cm injection for 3 ~ 5 sec, and 200 to 230 V/cm separation. In the results, the separation efficiency of mixed cations are not clear enough to distinguish one peak from another, but it is a good separation for simultaneous measurement of Na+ and CH3COO-. In this study, we have developed the conductivity detection in capillary electrophoresis system.