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In the present study, a comparison between a disposable electrochemical DNA biosensor and a Vibrio fischeri-based luminescent sensor for the detection of toxicants in water samples was made.In order to realize this study, a disposable electrochemical DNA biosensor has been reported. The DNA biosensor is assembled by immobilizing double stranded Calf Thymus DNA onto the surface of a disposable carbon...
A portable surface plasmon resonance (SPR) optical biosensor device is described as a direct immunosensing system to determine organic pollutants in natural water samples. Monitoring of organochlorine (DDT), organophosphorus (chlorpyrifos) and carbamate (carbaryl) compounds within the concentration levels stipulated by the European legislation, can be accomplished using this immunosensor. The lowest...
The recent release of ca. 70,000tonnes of a heavy fuel oil from the Prestige-Nassau carrier along the Spanish northern coast, mainly along Galicia, was monitored using attenuated total reflectance—mid IR spectrometry. The fuel was characterized and differentiated from 10 products commonly transported along the Galician coast (and their series of weathered samples) using factor analysis. The Prestige's...
A highly sensitive, fast and stable conductometric enzyme biosensor for determination of nitrate in water is reported for the first time. The biosensor electrodes were modified by methyl viologen mediator mixed with nitrate reductase (NR) from Aspergillus niger by cross-linking with glutaraldehyde in the presence of bovine serum albumin and Nafion ® cation-exchange polymer. The process parameters...
This work describes the application of an optical biosensor (RIver ANALyser, RIANA) to the simultaneous analysis of three relevant environmental organic pollutants, namely, the pesticides atrazine and isoproturon and the estrogen estrone, in real water samples. This biosensor is based on an indirect inhibition immunoassay which takes place at a chemically modified optical transducer chip. The spatially...
Nanoscience and nanotechnology deal with the study and application of structures of matter of at least one dimension of the order of less than 100nm (1nm=one millionth of a millimetre). However, properties related to low dimensions are more important than size. Nanotechnology is based on the fact that some very small structures usually have new properties and behaviour that are not displayed by the...
The poor water solubility of the free base and the high dissociation constant (K a ) hinder mainly the assay of alkaloid salts. We have elaborated an enviroment friendly method that can be carried out in aqueous media. The stability difference of the cyclodextrin (CD) complexes of free and protonated bases were used for this purpose. The base is included into the hydrophobic cavity of the...
In this study, a new technique by hydride generation–atomic fluorescence spectrometry (HG–AFS) for determination and speciation of inorganic arsenic using multisyringe flow injection analysis (MSFIA) is reported. The hydride (arsine) was generated by injecting precise known volumes of sample, a reducing sodium tetrahydroborate solution (0.2%), hydrochloric acid (6M) and a pre-reducing solution (potassium...
Peroxynitrite was one of the important reactive oxygen species (ROS) which have been focused for many years. Peroxynitrite is an extremely strong and reactive oxidant which can cause many diseases linked to inflammatory processes and autoimmune diabetes, etc. ROS can significantly react with peroxidase and nicotinamide adanine dinucleotide (NADH) which is linked to numerous biological processes. NADH,...
Yeast-based bioassays are becoming widespread tools for detection and quantification of ligands for vertebrate nuclear hormone receptors, including estrogens, progestans, androgens and dioxin-like compounds, both for agonistic and for antagonistic effects. These systems rely on the monitoring of transcription rates of reporter genes whose expression in yeast depends on binding of receptors to their...
An inter-laboratory comparison exercise was conducted under the European Union funded project entitled: Screening Methods for Water Data Information in Support of the Implementation of the Water Framework Directive (SWIFT-WFD) and coordinated by the Consejo Superior de Investigaciones Científicas (CSIC), in order to evaluate the reproducibility of different toxicity tests based on the bioluminescence...
A sensor with potential for the development of a “chemical barcode” for real-time monitoring of fish freshness is described. This on-package sensor contains a pH sensitive dye, bromocresol green, that responds through visible colour change to basic volatile spoilage compounds, such as trimethylamine (TMA), ammonia (NH 3 ) and dimethylamine (DMA) collectively known as Total Volatile Basic Nitrogen...
Amberlite XAD-4 adsorber resin was modified with 8-hydroxy quinoline (Oxine) by equilibrating with methanol solution of the reagent and the modified resin was used as a support material for the solid phase extraction and preconcentration of UO 22+ from aqueous solution at pH between 4 and 5.5. Ten micrograms of uranium from 300ml of aqueous phase could be quantitatively extracted in to...
Formal validation, that is the study of the analytical performances of a method, is recognized as the best safeguard against the generation and publication of data with low reliability.Although the topic of HPTLC validations has been largely investigated, there is still a need for a general validation method applicable whenever a blank matrix cannot be reconstituted, notably herbs and their extracts...
The preservation of arsenic species in water samples is an indispensable method to avoid their changes during storage, if it is not possible to analyse them immediately. The aim of this investigation was to demonstrate the limitations of the suggested method by using phosphoric acid as a preservation agent. The samples remain stable for 3 months, even if they show evidence of high concentrations of...
A novel thin molecularly imprinted sol–gel film with specific recognition for cytidine was electrodeposited on the surface of piezoelectric quartz crystal (PQC) Au-electrode. In this method, a sufficiently negative potential was applied to the electrode surface to generate hydroxyl ions, which play the role of the catalyst for the hydrolysis and condensation of 3-(aminopropyl)trimethoxysilane (APTMS)...
Pharmaceutical residues in the environment, and their potential toxic effects, have been recognized as one of the emerging research area in the environmental chemistry. The increasing attention, on pharmaceutical residues as potential pollutants, is due that they often have similar physico-chemical behaviour than other harmful xenobiotics which are persistent or produce adverse effects. In addition,...
A new technique to analyze aqueous samples for nanograms per liter levels of volatile and semivolatile compounds using microextraction and thermal desorption into a gas chromatograph/ion trap mass spectrometer (GC/MS) is described. This method is inherently sensitive (50mL of aqueous sample is extracted prior to each desorption), uses no solvents, and detects volatiles and semivolatiles in the same...
Mass-balance data were acquired using fluorescence spectrometry for 2-naphthol and three polycyclic aromatic hydrocarbon (PAH) metabolites using liquid–liquid–liquid microextraction and liquid–liquid microextraction systems. The PAH metabolites are very important biomarkers, and there has been no previously reported mass-balance data on these compounds with microextraction systems. In addition, the...
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