Desenvolupament de biosensors per tecnologia planar per a l'anàlisi agroalimentària

Consultable des del TDXTítol obtingut de la portada digitalitzadaDurant la tesi doctoral s'ha comprovat que a partir de biosensors fabricats mitjançant una tecnología relativament senzilla i económica, com és la formació de matrius i la impressió serigràfica de tintes, es poden realitzar determinacions de diversos analits d'interès en l'àmbit alimentari no tan sols en solucions estàndard sinó també en mostres reals. Els resultats aconseguits suposen una important millora en l'abaratiment dels costos d'anàlisi i la reducció del temps necessari. El treball realitzar s'ha portat a terme en dues parts molt diferenciades; en una primera s'han desenvolupat biosensors screen-printing basats en resines epoxi per a l'anàlisi de pesticides i en una segona biosensors screen-printing basats en matrius de sílice (sol-gel) per a la determinació d'àcid màlic i làctic en vins

Enzymatic Determination of Diglyceride Using an Iridium Nano-Particle Based Single Use, Disposable Biosensor

A single use, disposable iridium-nano particle contained biosensor had been developed for the determination of diglyceride (DG). In this study hydrogen peroxide, formed through the enzymatic breakdown of DG via lipase, glycerol kinase and glycerol 3-phosphate oxidase, was electrochemically oxidized at an applied potential of +0.5 V versus the Ag/AgCl reference electrode. The oxidation current was then used to quantify the diglyceride concentration. Optimum enzyme concentrations and the surfactant loading used were established for successful sensor response. Good linear performance was observed over a DG concentration range of 0 to 25 μM in phosphate buffer and bovine serum media

Evaluation of a novel pad printing technique for the fabrication of disposable electrode assemblies

The viability of using a pad printing technique for the production of disposable electrode systems has been assessed. The morphology and structural characteristics of the carbon ink layers has been characterised and the electrochemical behaviour of the resulting layers investigated using a number of model systems. Voltammetric and potentiometric methodologies (in aqueous buffer and acetonitrile) were conducted using ferrocence carboxylic acid and naphthoquinone-thiol systems. The ability to create modified electrode assemblies through the incorporation of indicators directly within the ink prior to printing has been shown to provide a facile means through which the selectivity of the electrodes can be enhanced and provides a quick means of prototyping reagentless sensors. © 2004 Elsevier B.V. All rights reserved

Iron(III) oxide graphite composite electrodes: Application to the electroanalytical detection of hydrazine and hydrogen peroxide

Composite electrodes based on iron(III) oxide, Fe2O3, carbon powder and epoxy resin have been prepared and characterized using electrochemical methods and X-ray photoelectron spectroscopy (XPS). Initially composite electrodes were made by mixing micron sized carbon powder surface with iron(III) oxide. However, the voltammetric responses were unsatisfactory. Therefore, a new type of composite electrodes was made using carbon powder modified with iron(III) oxide via a wet impregnation procedure. This technique involves saturation of the carbon powder with iron(III) nitrate followed by thermal treatment at ca. 623 K forming iron(III) oxide on the surface of the carbon powder. Several key parameters such as percentage of carbon powder and iron(III) oxide as well as electrode geometry (electrode length) have been optimized. Composite electrodes show attractive performances for the electrochemical detection of hydrogen peroxide and hydrazine with detection limits of 0.12 μM and 1.18 μM respectively. These limits of detection are comparable to the detection limits attained by alternative analytical techniques and are lower than that obtained by other electroanalytical methods. © 2006 Wiley-VCH Verlag GmbH and Co. KGaA