Rafael J. Garcia-Villanova

Rafael J. Garcia-Villanova
Universidad de Salamanca · Departamento de Química Analítica, Nutrición y Bromatología

About

54
Publications
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993
Citations
Citations since 2016
1 Research Item
364 Citations
20162017201820192020202120220102030405060
20162017201820192020202120220102030405060
20162017201820192020202120220102030405060
20162017201820192020202120220102030405060

Publications

Publications (54)
Book
Full-text available
Fruto de más de 25 años de investigación del autor sobre los subproductos de desinfección-cloración de las aguas, este libro trata de poner al día lo conocido de la reacción del cloro —con gran diferencia el desinfectante universal— con la materia orgánica natural de las aguas, su forma de aplicación, los procedimientos de optimización del tratamie...
Article
Most methods for the analysis of haloacetic acids published in recent years are based on ion chromatography with direct injection, employing a gradient elution with potassium hydroxide (KOH). This work reports the exploration of an alternative eluent, a buffer of sodium carbonate/sodium hydrogen carbonate, aimed at the simultaneous analysis of nine...
Article
Full-text available
Because of their historically high records of disinfection by-products, four water bodies serving as sources for drinking water in four cities of Castilla y León, Spain, were selected for a further study. With moderate to high contents of organic matter, an important part of it corresponded to algal biomass, as confirmed by the enormous values of c...
Article
Bromate was first reported as a disinfection by-product from ozonated waters, but more recently it has been reported also as a result of treatment using hypochlorite solutions worldwide. The aim of this study was to study the scope of this phenomenon in the drinking waters (n=509) of Castilla y León, Spain, and in the hypochlorite disinfectant reag...
Article
Full-text available
This article explains the general difficulties of the Spanish source waters and climatic conditions regarding a control of trihalomethanes (THMs), as reflected by the case of Castilla y León, and how the median values of 75 and 163 microg L(-1) of years 1999 and 2002 gave way to the more moderate of 31 and 47 microg L(-1) of years 2006 and 2007, re...
Article
The potential of the near infrared spectroscopy (NIRS) technique for the analysis of red paprika for aflatoxin B(1), ochratoxin A and total aflatoxins is explored. As a reference, the results from a chromatographic method with fluorescence detection (HPLC-FD) following an immunoaffinity cleanup (IAC) were employed. For the NIRS measurement, a remot...
Article
Aflatoxins are the only mycotoxins with legal limits for spices in the European Union. A further limit for ochratoxin A is expected to be adopted soon. Thus, rapid simultaneous methods for quantifying the five mycotoxins are sought. Liquid extraction, immunoaffinity column cleanup, and HPLC-FD with a wavelength program were optimized for the analys...
Article
Full-text available
An early optimisation of the o-phthaldialdehyde (OPA) method for the HPLC-fluorimetric analysis of amino acids in honey and bee-pollen made feasible the quantification of 23, which included five infrequently searched for. Forty samples of monovarietal dark honeys, from four botanical origins, were analysed for their amino acids’ profile (which incl...
Article
In the present work, we study the use of near infra-red spectroscopy (NIRS) technology together with a remote reflectance fibre-optic probe for determination of the major components in bee pollen. The method allows immediate control of the bee pollen without prior sample treatment or destruction through direct application of the fibre-optic probe t...
Article
Full-text available
An optimization of the OPA method has made feasible separation and quantification of 23 amino acids, which include 5 infrequently searched for. Detection limits ranged from 0.24 to 10.1pmol in honey and from 29.1 to 0.42pmol in bee-pollen; reproducibility (C.V.) ranged from 5.3% to 20.4%; recoveries were above 78.8%. Forty monovarietal honey sample...
Book
A description of biotic and abiotic hazards that may arise to food at any stage from primary production, processing, storage, distribution, delivery, sale, cooking and intake by humans. A second part is a theoretical introduction to the principles of the Hazard Analysis and Critical Control Points System, with a practical aproach and examples on ho...
Article
Full-text available
Bee pollen is a major substrate for mycotoxins growth when no prompt and adequate drying is performed by the beekeeper after collection by bees. Regulatory limits for aflatoxins and ochratoxin A are currently in force in the European Union for a rising list of foodstuffs, but not for this. An immunoaffinity column cleanup process has been applied p...
Article
Full-text available
New and more stringent standards have been stablished or are under way in many countries for disinfection by-products (DBPs) in drinking water. The effort to comply with these new rules, maintaining microbiological security, may be quite unequal for each country since different water resources (surface or groundwater), water qualities and even clim...
Article
Full-text available
 Sixty honey samples from six different production zones of the provinces of Salamanca, Zamora and Cáceres (west Spain) were analyzed for 13 common legal physico-chemical parameters and 17 sugars in order to test for their geographical classification. Application of linear stepwise discriminant analysis to a number of variables made of a selection...
Article
Full-text available
Sixty honey samples from six different production zones of the provinces of Salamanca, Zamora and Cáceres (western Spain) were analysed for 13 common legal physicochemical parameters and 17 mineral elements (13 cations and four anions) in order to test for their geographical classification. Application of linear stepwise discriminant analysis to a...
Article
Full-text available
A capillary gas chromatographic method has been developed for simultaneous determination of at least 18 sugars (2 monosaccharides, 11 disaccharides and 5 trisaccharides) in honey, as their oxime-trimethylsilyl ethers. The chromatographic conditions have been systematically and thoroughly optimized, to eliminate the peak overlap commonly reported fo...
Article
Full-text available
Six sampling points located at different distances, two by two (near-far), from the three main supply reservoirs, were selected in the distribution system of the drinking water network of the city of Salamanca in order to follow the evolution of trihalomethanes (THMs). Data obtained were correlated statistically with the chlorination dosages in the...
Article
Full-text available
Taking samples at eight points chosen from two conventional water treatment plants for the city of Salamanca, the formation and evolution of THM levels were studied on 11 different dates. The values obtained were correlated statistically with the following parameters: concentration of humic acids (only raw water), pre- and postchlorination dosages,...
Article
Full-text available
A comparative study is made of the application of liquid−liquid (LLE) and liquid−solid (LSE) extraction techniques with a new sorbent with trifunctional bonding chemistry (tC18) for environmental sampling and trace enrichment. The experimental conditions of the LLE and LSE methods were evaluated for the determination of 22 organochlorine and 2 orga...
Article
Full-text available
A comparative study has been made of the application of the liquid−solid extraction (LSE) technique using a new sorbent solid, tC18, and liquid−liquid extraction (EPA Method 610) of 11 polycyclic aromatic hydrocarbons (PAHs) considered by the EPA as priority pollutants. The experimental conditions of both extraction techniques are evaluated and app...
Article
Full-text available
Three groups of organic parameters of surface waters are evaluated for their analytical methodology. A comparison of the Methylene blue versus the Cupric o-phenantroline methods for anionic surfactans is made, with the result of a proposal for replacement of the first official one by the second. Assuming that for the parameter "Pesticides and Simil...
Article
Full-text available
Diacetyl and 2,3-pentanedione react with isoniazide in acidified solutions to give the corresponding hydrazones which, by reacting with a zirconium (IV) salt, form fluorescent complexes. Both reactions have been studied separately. Variables such as pH, heating time, and excess of reactives are discussed. The method may be used for the determinatio...
Article
Full-text available
A method has been worked out for the spectrophotometric determination of total vicinal diketones. It is based on the distillation of diacetyl and/or 2,3-pentanedione, the subsequent condensation with isoniazide (yielding the corresponding hydrazones), the complexation with zirconium(IV) and the photometric measurement of the resulting yellow comple...
Article
Full-text available
The experimental conditions of a simple liquid—liquid extraction method for the determination of sixteen volatile halo-organic compounds, including the main trihalomethanes (THMs), in water were evaluated. The volatile halo-organic compounds were extracted with n-pentane and analysed by gas chromatography using a semi-capillary column and an electr...
Article
Full-text available
We report on a simple extraction technique using n-pentane and later chromatographic analysis of 16 volatile halo-organic compounds in the raw and chlorinated water of six towns of the province of Salamanca (Spain). The four principal trihalomethanes (THMs) and 1,1,2-trichloroethane were detected in the treated water, the highest concentrations lev...
Article
The onset of a performant method for the determination of 16 volatil haloorganic hydrocarbons, chlorination by-products (including the 4 THMs), has enable us with a certain accuracy to make a following-up of the level of theses compounds in the raw waters, during the potabilization processes and in the distribution system for the city of Salamanca....
Article
Full-text available
Se ha desarrrollado un método espectrofotométrico para la determinación de diacetilo, basado en la formación de diacetildiisonicotin hidrazona, por reacción de diacetilo con isoniacida. La hidrazona compleja con Zr(IV) a pH ácido (1,7) formando un quelato amarillo y soluble. Su absortividad molar es 1,7x10(exp4) l/mol.cm a 410 nm. El método ha sido...
Article
Se presenta una revisión de todo lo descrito hasta el presente sobre las llamadas dicetonas vecinales o alfa-dicetonas: diacetilo y 2,3-pentanodiona. Su presencia, origen, transformación, control, eliminación y análisis en los alimentos. Los autores has elaborado esquemas que desdcriben los mecanismos de formación y transformación descritos —en los...
Article
Full-text available
RESUMEN Se ha aplicado el método de determinación del ác¡do fítico, propuesto por nosotros, a la valoración de este compuesto en harinas dietéticas de uso frecuente en la alimentación infantil. EI método, basado en una complexometría indirecta con Fe(lll) y ácido sulfosalícílico como indicador, resulta idóneo por Ia sencillez, precisión y exactitud...

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