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| Author(s): |
Heron Dominguez Torres da Silva
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) |
| Defense date: | 2006-09-04 |
| Examining board members: |
Claudimir Lucio do Lago;
Mario Cesar Ugulino de Araújo;
Luiz Otávio Saraiva Ferreira;
Jivaldo do Rosario Matos;
Eliphas Wagner Simões
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| Advisor: | Claudimir Lucio do Lago |
| Abstract | |
Microfabrication processes and devices for hydrodynamic and electroosmotic manipulation were developed based on toner-polyester, toner-glass and toner-as-resist techniques. Additionally, techniques to perforate glass slides and sealing of glass devices were introduced. Microdevices for capillary electrophoresis and electrospray for mass spectrometry were developed using these techniques. The characterization of the materiais and the processes demonstrated that the devices obtained by the toner-polyester process are compatible with the media used for capillary electrophoresis. The detection of alkaline ions with capillary electrophoresis with contactless conductivity detection was demonstrated. The typical cross shape microstructure was designed with a 22-mm long and 12-µm deep separation channel. The conductivity cell was implemented with 1-mm wide adhesive copper stripes. The applied signal was 530kHz and 10Vpp . The separation of 100µmo1L-1 K+, Na+, and Li+ was accomplished in 0.8 min under a voltage of 1 kV. Another toner-polyester microchip was developed to demonstrate its usefulness for electrospray/mass spectrometry. Solutions of 1 mmol L-1 potassium chloride and 1 mmol L-1 glucosamine in water/methanol 1:1 (v/v) were introduced with stable current of 100 nA without corona discharge. Capillary electrophoresis with amperometric detection was also demonstrated. The separation of iodide (10 mmol L-1) and ascorbate (40 mmol L-1) was carried out at 4.0 kV (800 V cm-1) with detection potential of 0.9 V (vs. Ag/AgCl), electrokinetic injection at 1.0 kV/10 s, running buffer of sodium borate 10 mmol L-1 with CTAH 0.2 mmol L-1 , pH 9.2. The efficiency was 1.6.104 plates/m and the limits of detection were 500 nmol L-1 (135 9mol) and 1.8 µmol L-1 (486 amol) for iodide and ascorbate, respectively. The toner-glass process was proposed and conductivity and photometric detections were demonstrated for the devices generated by this new technique. The separation of 200 pmol L-1 K+, Na+, and Li+ was achieved in buffer histidine/lactic acid 30 mmol L-1 water/methanol 9: 1 (v/v), electrokinetic injection at 2.0 kV/5.0 s, separation potential of 1 kV, and contactless conductivity detection at 530 kHz and 2.0 Vpp. The photometric detection of methylene blue at 660 nm was carried out in sodium borate 20 mmol L-1 (pH 9.2). (AU) | |