State-of-the-Art of (Bio)Chemical Sensor Developments in Analytical Spanish Groups

(Bio)chemical sensors are one of the most exciting fields in analytical chemistry today. The development of these analytical devices simplifies and miniaturizes the whole analytical process. Although the initial expectation of the massive incorporation of sensors in routine analytical work has been truncated to some extent, in many other cases analytical methods based on sensor technology have solved important analytical problems. Many research groups are working in this field world-wide, reporting interesting results so far. Modestly, Spanish researchers have contributed to these recent developments. In this review, we summarize the more representative achievements carried out for these groups. They cover a wide variety of sensors, including optical, electrochemical, piezoelectric or electro-mechanical devices, used for laboratory or field analyses. The capabilities to be used in different applied areas are also critically discussed

Applications of Molecularly Imprinted Films

Molecularly imprinted polymers are materials that have voids that are complementary in shape, size, and electronic environment to a specific molecule used for preparation, known as the template. These voids are specific recognition sites that bind the templates preferentially and are used specifically for biomimetic sensors and for solid-phase extraction. Because the specific surface is very important during this process, the use of films and membranes is preferred. This book contains four articles dedicated to sensor application (three research articles and one review) and one research article dedicated to solid-phase extraction

Carbon and Platinum Nanostructured Electrodes on Miniaturized Devices for Biomedical Diagnostics

Nowadays, medical devices face several limitations concerning rapid, reliable and simultaneous quantification of a set of ions and metabolites from a micro-nanoliter volume of undiluted samples. The development of minimally-sized devices is, therefore, of key importance. In such a context, electrochemical sensors are particularly advantageous because of the simple, low cost and reproducible fabrication procedures and the rapid analytical measurements. Moreover, they provide easy possibilities for continuous monitoring. However, sensitive and selective detection of molecules in the physio-pathological concentration range is very challenging when conventional electrochemical devices are employed, especially for long-term use. Nanostructured electrodes are considered as one of the most promising strategies to overcome issues of sensitivity because of their large surface area and their excellent electrocatalytic properties. They could also address in part the problem of selectivity due to shifts in potential of the measured Faradic currents. In addition, nanomaterials could provide stable and reproducible potential responses when used as solid-contact materials of ion-selective electrodes. Inappropriate nanointegration methods could decrease the sensor performance so that the development of tailored nanostructuration protocols is extremely important to boost the sensor sensitivity, selectivity and stability over time. Objective of this thesis was to design and electrochemical characterise novel carbon and metal nanostructures for medical sensors. First of all, the integration of carbon nanomaterials on specific sensing sites of a microfabricated sensor was considered. Time-consuming, expensive and hardly-reproducible nanostrucuturation approaches contemplate the co-immobilization of carbon nanomaterials and additives whose presence inevitably masks the nanomaterial promising properties and compromises the time-stability in aqueous environments. The selective CVD growth of carbon nanomaterials was considered as a promising method to enable the coupling nanomaterial-electrode. Deposition parameters were optimised to make the process compatible with CMOS temperatures. Then, new protocols based on rapid electrodeposition methods were developed to integrate differently shaped and sized Pt and Pt-Au nanostructures on electrochemical platforms. Template-free electrodeposition was selected because of the durably-anchored and the contaminant-free coatings resulting after the process. Both nanostructuration approaches generated highly-sensitive electrodes to detect human metabolites as compared with the bare counterparts. Unprecedented sensing performance were obtained by both direct and enzyme-mediated detection mechanisms. Selective sensing was achieved thanks to the capability of the proposed nanostructured electrodes to discriminate the detection potentials of biomarkers from those of interfering species. The developed nanostructures were also excellent solid contacts between an electrode and an ion-selective membrane resulting in stable and reliable solid-contact ion-selective electrodes. To prove their stability and reproducibility for long operating lifetimes, these ion-selective electrodes have been successfully used as standard for continuous acute cell death monitoring

Investigation of Volatile Organic Compounds (VOCs) released as a result of spoilage in whole broccoli, carrots, onions and potatoes with HS-SPME and GC-MS

Vegetable spoilage renders a product undesirable due to changes in sensory characteristics. The aim of this study was to investigate the change in the fingerprint of VOC composition that occur as a result of spoilage in broccoli, carrots, onions and potatoes. SPME and GC-MS techniques were used to identify and determine the relative abundance of VOC associated with both fresh and spoilt vegetables. Although a number of similar compounds were detected in varying quantities in the headspace of fresh and spoilt samples, certain compounds which were detected in the headspace of spoilt vegetables were however absent in fresh samples. Analysis of the headspace of fresh vegetables indicated the presence of a variety of alkanes, alkenes and terpenes. Among VOCs identified in the spoilt samples were dimethyl disulphide and dimethyl sulphide in broccoli; Ethyl propanoate and Butyl acetate in carrots; 1-Propanethioland 2-Hexyl-5-methyl-3(2H)-furanone in onions; and 2, 3-Butanediol in potatoes. The overall results of this study indicate the presence of VOCs that can serve as potential biomarkers for early detection of quality deterioration and in turn enhance operational and quality control decisions in the vegetable industry

NOTIFICATION !!!

All the content of this special edition is retrieved from the conference proceedings published by the European Scientific Institute, ESI. http://eujournal.org/index.php/esj/pages/view/books The European Scientific Journal, ESJ, after approval from the publisher re publishes the papers in a Special edition

NOTIFICATION !!!

All the content of this special edition is retrieved from the conference proceedings published by the European Scientific Institute, ESI. http://eujournal.org/index.php/esj/pages/view/books The European Scientific Journal, ESJ, after approval from the publisher re publishes the papers in a Special edition

NOTIFICATION !!!

All the content of this special edition is retrieved from the conference proceedings published by the European Scientific Institute, ESI. http://eujournal.org/index.php/esj/pages/view/books The European Scientific Journal, ESJ, after approval from the publisher re publishes the papers in a Special edition