Eletroforese em microssistemas: desenvolvimento instrumental, microfabricação e análise de nitrosotióis

• Autor(a) principal: Duarte Junior, Gerson Francisco
• Data de Publicação: 2019
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/001300000817c
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/10217
• topic: Microchips; Eletrólise; Carboidratos; NOA; RSNO; Electrophoresis microchips; Electrolysis; Carbohydrates; NOA; Low-molecular-weight; S-nitrosothiols; CIENCIAS EXATAS E DA TERRA::QUIMICA

Microchip electrophoresis (ME) has become an important tool in analytical and bioanalytical chemistry applications. Miniaturization of analytical devices include several advantages and the development of new systems and methods are needed. This thesis presents some instrumental advances in ME, including separation of carbohydrates that was possible minimizing the electrolysis phenomena, the manufacture of ME in glass using a photo-curable resin, and a procedure for integrated analysis of s-nitrosotióis. The separation of fructose, galactose, lactose, glucose and sucrose in commercial microchips using an apparatus, built to minimize electrolysis, is presented. The apparatus consists of additional reservoirs, which are connected to the reservoirs of the microchip through a saline bridge. The separations were performed using an electrolyte composed by NaOH (75 mmol/L) and Na 3 PO 4 (15 mmol/L) and monitored by capacitively coupled contactless conductivity detection (C 4 D). Efficiencies ranging from 45000 to 70000 plates/m were achieved. The system offered good linearity from 1 to 10 mmol/L and LOD between 150 and 740 μmol/L. The manufacture of microchips using glass and NOA (Norland Optical Adhesive), a photo-curable resin, for application in electrophoresis was proposed. Simplicity in the manufacturing process allows research centers still under development to produce their glass microsystems simply and quickly. Studies to evaluate morphology, magnitude and stability of electroosmotic flow and solvent compatibility were performed. S-nitrosothiols (RSNO) are very important biomolecules that play crucial roles in many physiological and physiopathological processes, acting as NO donors. One, two or more RSNO can then be combined to design a drug and therefore, the quantification of each is important to establish an acceptable quality control process. This study reports on an original and integrated microdevice allowing for the successive electrokinetic separation of low molecular weight RSNOs, their decomposition under metal catalysis, and their quantitation by amperometric detection of the produced nitrite in the end- channel arrangement, leading to their quantitation in a single run. Different operating and running parameters were optimized to achieve the best analytical data, allowing for an LOD equal to 20 μM. The simultaneous separation of S-nitrosoglutathione and S-nitrosocysteine was successfully obtained within 75 s. The proposed methodology using SU-8/Pyrex microfluidic devices opens new possibilities to investigate future drug candidates for NO-donors.