Juan Manuel Fernández-Romero

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A new flow injection (FI) method for photometric monitoring of cyanate in bioremediation processes using immobilised native cyanase is described. The method is based on the catalytic reaction between cyanate and bicarbonate to produce ammonia and carbon dioxide in the presence of an inducible native cyanase, immobilised in a reactor packed with glass beads.(More)
A liquid chromatography (LC) method with luminescence detection for the determination of eight quinolone antibiotics is reported. The system encompasses three consecutive steps: (a) chromatographic separation using reverse-phase mode (RP-LC), (b) postcolumn derivatization reaction, and (c) luminescence detection by monitoring fluorescence (FL) and(More)
Several photometric and fluorimetric methods are proposed for the determination of cholesterol by use of enzymes immobilized on controlled-pore glass and the normal and stopped-flow injection modes, achieving linear ranges of the calibration curves between 26-776 mumol/l and 5-265 mumol/l with excellent regression coefficients and good coefficients of(More)
The steps involved in the methods for the determination of vitamin D3 metabolites (namely, 25-hydroxyvitamin D3, 1,25-dihydroxyvitamin D3, 24,25-dihydroxyvitamin D3) mainly in clinical samples are critically reviewed. Sample pretreatment (e.g. deproteinization, saponification, liquid liquid and liquid solid extraction, etc.) as a function of both type of(More)
A method for the evaluation of liposome size populations using sucrose density gradient centrifugation coupled with a continuous flow system is presented. Liposomes, prepared using different methods (rapid solvent evaporation, rehydration, and detergent removal) and modified by assaying several procedures (shaking, sonication and extrusion) were evaluated(More)
Open-closed flow injection systems allow the development of methods based on multidetection by using conventional detectors. The methods proposed here for the determination of alanine aminotransferase (ALT) utilize a photometric detector included in the closed circuit, which allows one to perform fixed-time and reaction-rate measurements whose sensitivity(More)
A new post-column derivatization system is described and applied to the determination of flavonoids in citric beverages after their separation by LC using a monolithic column. The derivatization involves the formation of the chelates of the analytes with aluminum (III) and terbium (III) in the presence of the surfactant SDS and the measurement of the(More)
A commercially available supercritical fluid extractor provided with carbon dioxide was coupled to a dual-beam thermal lens spectrometer with a pumpprobe coaxial configuration, pumped by a pulsed Nd-YAG laser operating at the fundamental wavelength of 1064 nm. As a preliminary step, several compounds were studied in batch regime using carbon tetrachloride(More)
Several methods are proposed for the enzymatic determination of total cholesterol in serum by flow injection analysis (FIA). The use of the merging-zones mode, with or without halting of the reacting plug in the photometric or fluorimetric detector, has allowed the development of four precise methods for the determination of this analyte; calibration curves(More)
Approaches based on continuous separation units coupled to either liquid or gas chromatography for improving the features of analytical methods are proposed. Examples of solid-phase separation-liquid chromatography for the determination of fat-soluble vitamins and their metabolites in clinical samples, and pervaporation-gas chromatography for the(More)