The use of a new twin-electrode thin-layer cell to the study of homogeneous processes coupled to electrode reactions

Three electrode electrochemical microfluidic cell: construction and characterization

“…The option for these ions as model analytes is supported by the potentiality of the gold working electrode used in the microcell to analyze these metals, as described in the literature. 24,25 Figure 4 presents the signals obtained for the simultaneous analysis of copper and mercury using potentiometric stripping analysis at constant current as function of the increasing concentrations of both metals (10,20,30,40 and 50 µg L -1 ). These chronopotentiograms were recorded using a flow rate of 60 µL min -1 and deposition time of 60 s. A comparison between the performance of the flow-through microcell with a conventional flow-through cell 26 shows a similar sensitivity for both cases, however, the flow rate necessary for the conventional cell to present the same response must be superior to 3.0 mL min -1 .…”

“…After publication of these works, a number of new applications were presented in the literature based on this procedure. Some examples are: construction of amperometric microdetectors for conventional capillary electrophoresis system 5 and separation microsystems manufactured in polyester toner, 6 microfluidic cells with interdigitated array gold electrodes, 7 generator-collector electrochemical microdevices, [8][9][10] production of microchannels in glass, 11,12 microfluidics devices for sample treatment, 13,14 new procedures for flow rate control and sample injection in microfluidic cells, 15 microelectrode arrays, 16 electrodes with reproducible area, 17 integration of planar electrodes for contactless conductivity detection on polyester-toner electrophoresis microchips, 18 insertion of passive micromixers in microfluidic devices 19 and construction of electrochemical microcells containing the working, counter and reference electrodes in the same device. 20 In this work a simple methodology for the construction of flow through microcells with introduction of the three electrodes (working, counter and pseudo-reference) in microchannels is described.…”

“…Previous studies have demonstrated that it is possible to reach 45 µm of height. 7,8,10 (B) Using the same procedure described in (A), another mask that defines the positioning of counter and pseudo reference electrodes, as well as the orifice of inlet and outlet of the solution is drawn. The mask, once printed, is heat transferred to a polycarbonate substrate, obtained from recordable CDs (after removal of the silver film).…”

Cheap and disposable gold and silver electrodes: Trends in the application of compact discs and digital versatile discs for electroanalytical chemistry

“…The low cost the disc means they can be, if needed, treated as disposable one shot devices. Further modifications can also be made by techniques such as laser [14] and inkjet printing [12,15,16] or by the heat transfer of toner masks [17][18][19][20][21][22][23] designs onto the metal surface. Other alternative methods for the economic fabrication of electrodes exist and have been widely used and…”

Uso da pressão gerada por uma coluna de água para controle da vazão em sistemas de análises em fluxo

“…Como limitações podem ser citadas, o custo relativamente elevado da bomba (≈US$ 1.500,00) e o ruído gerado na linha base pela pulsação do fluido transportador, o que é particularmente importante quando da utilização de detectores amperométricos ou voltamétricos (sensíveis à vazão) 1 . Problemas relacionados à geração de ruídos na linha base são ainda mais acentuados quando se utilizam bombas peristálticas para o controle da vazão de sistemas de análise miniaturizados com detecção eletroquímica [2][3][4][5] . Estudos para contornar este tipo de limitação são necessários, pois atualmente há uma tendência na implementação de sistemas de micro-FIA.…”