Electrochemistry is the study of redox chemical reactions at the surface an electrode. In our case, it provides a simple, fast, an inexpensive way to perform detection of analytes at low concentrations. Here are described several of the project that we have recently published in this area.
Rational Development of Electrochemical Biosensors
Electrochemical biosensors offer a wide variety of advantages including simplicity and low cost. As an example, the flow injection analysis (FIA) of monosodium L-glutamate (MSG) was performed electrochemically using a biosensor based on screen-printed electrodes containing carbon nanotubes (CNT). The sensor was fabricated by simply adsorbing glutamate oxidase (GlutOx) on the electrode surface and provided wide linear range (0.01–10 µM) with low detection limit (10 nM, S/N≥3), fast response time (≤5 s), and good operational and long-term stability.
Optically Transparent Carbon Electrodes (OTCE)
Among other carbon-based nanomaterials suitable for electrochemistry, optically transparent carbon electrodes (OTCE) are particularly attractive because they offer properties that are similar to those of carbon nanotubes including good electrical conductivity, high stability in acidic and basic solutions, wide potential window, and adequate robustness. In order to bolster the development of new applications, we have described different alternatives for the fabrication of nanostructured, uniform, transparent, and conductive OTCE obtained by pyrolysis of either photoresist or biological precursors. These precursors (e.g. proteins) were selected based on their characteristics (elemental composition, size, solubility, and cost) and deposited on solid substrates by simple adsorption from an aqueous solution. The resulting electrodes were characterized in terms of topographical, optical, and electrochemical properties and used for the development of an electrochemical biosensor for glucose.
In order to provide a point-of-care system and overcome drawbacks associated with the fabrication of devices, a new hybrid platform was proposed. The platform is centered on the use of 5 interconnecting microfluidic components that serve as either the injector or reservoirs. These plastic units are interconnected using standard capillary tubing, enabling in-channel detection by a wide variety of standard techniques, including capacitively coupled contactless conductivity detection (C4D). This electrochemical detection method has captured the attention of many researchers. In our case, the presented approach (named 52-platform) offers a previously unseen versatility, enabling the assembly of the platform within minutes using capillary tubing that differs in length, diameter, or material. The advantages of the proposed design are demonstrated by performing the analysis of inorganic cations by capillary electrophoresis on soil samples from the Atacama Desert..