Monitoring winemaking process using tyrosine influence in the excitation-emission matrices of wine.

Wine samples collected during the winemaking process have been analyzed employing a previously optimized UHPLC-FD method, determining their biogenic amines and amino acids profile. The results obtained have been submitted to a statistical analysis from which it was extracted that the most influential analyte was tyrosine. Thanks to its fluorescence, a method for its determination by excitation-emission matrices has been proposed.

Automated chromatographic method with fluorescent detection to determine biogenic amines and amino acids. Application to craft beer brewing process.

The combined determination of biogenic amines and amino acids is a challenge for food scientists. In this research, a new methodology for the automatic on-line precolumn derivatization and determination of 8 biogenic amines and 9 precursor amino acids by Ultra-High Performance Liquid Chromatography with fluorescent detection has been developed. The method derivatized the analytes with o-phthaldialdehyde and achieved the separation of the 17 derivatives in less than 15 min, obtaining good quality parameters (limits of detection varied between 7.

Dispersive liquid-liquid microextraction for a rapid determination of glyoxal in alcoholic beverages.

Carbonyl compounds, like glyoxal, methylglyoxal, diacetyl or pentane-2,3-dione, among others, have been widely studied. Besides its endogenous origin, they are originated from foodstuffs and are related to sensorial characteristics in products such as wine and beer. Generally, for their determination, the analytes must be derivatised to adapt them for the detection system and this step takes long time.

Novel HPLC--Fluorescence methodology for the determination of methylglyoxal and glyoxal. Application to the analysis of monovarietal wines "Ribera del Guadiana".

The determination and quantification of α-dicarbonyl compounds, glyoxal and methylglyoxal, in "Ribera del Guadiana" monovarietal wines (Extremadura, Spain) without sample clean-up has been carried out by HPLC with spectrofluorimetric detection (307/371 nm). For this purpose, a derivatization step with the new reagent 3,4-diaminopyridine at pH 2 during 120 min at 90 °C has been included. Afterwards, the sample could be injected in the chromatographic system with no clean-up, during a total run time of 4 min.

Determination of chemotherapeutic drugs in human urine by capillary electrophoresis with UV and fluorimetric detection using solid-supported liquid-liquid extraction for sample clean-up.

Capillary electrophoresis was used for the rapid determination of three chemotherapeutic drugs employed to treat colorectal cancer: irinotecan, tegafur, and leucovorin, and their main metabolites (7-ethyl-10-hydroxycamptothecin and 5-fluorouracil), in human urine samples. A phosphate buffer (pH 11.34; 20 mM) was selected as the background electrolyte.

Green analytical determination of emerging pollutants in environmental waters using excitation-emission photoinduced fluorescence data and multivariate calibration.

An eco-friendly strategy for the simultaneous quantification of three emerging pharmaceutical contaminants is presented. The proposed analytical method, which involves photochemically induced fluorescence matrix data combined with second-order chemometric analysis, was used for the determination of carbamazepine, ofloxacin and piroxicam in water samples of different complexity without the need of chromatographic separation. Excitation-emission photoinduced fluorescence matrices were obtained after UV irradiation, and processed with second-order algorithms.

Evaluation of liquid chromatographic behavior of lumazinic derivatives, from α-dicarbonyl compounds, in different C18 columns: application to wine samples using a fused-core column and fluorescence detection.

Several C18 columns, packed with totally porous particles of different sizes and shell thicknesses, have been compared for simultaneous determination of α-dicarbonyl compounds, previous derivatization to lumazinic derivatives. Chromatographic conditions for the separation have been optimized for each column, and chromatographic parameters have been calculated and exhaustively compared. A core-shell C18 column provided the best results, and a HPLC method with fluorimetric detection has been proposed.

Development of a method for the determination of advanced glycation end products precursors by liquid chromatography and its application in human urine samples.

A liquid chromatographic method with fluorimetric detection has been developed to determine the most abundant α-dicarbonyl compounds, generated as intermediates in the Maillard's reaction, previous derivatization to high fluorescent pteridinic derivatives. Hence, the biomarkers D-glucosone, 3-deoxyglucosone, glyoxal, methylglyoxal, diacetyl, 2,3-pentanedione, and phenylglyoxal were quantified using a gradient elution mode. The experimental conditions of the derivatization reaction and mobile phase composition were optimized.

First-order multivariate calibration applied to the simultaneous fluorometric determination of the anticancer agents CPT-11 and SN-38 in serum and urine samples.

The first-order multivariate calibration method was used for the simultaneous determination of the camptothecin derivative, CPT-11 and its main metabolite, SN-38. The method is based on the fluorescence emission of these compounds in acidic media (acetate buffer, pH 4.75) and in the presence of ethanol (50%).

Spectrofluorimetric determination of SN-38, a promising new anti-tumor agent, in the presence and absence of organized media.

This study focuses on the spectrofluorimetric behavior of the camptothecin derivative 7-ethyl-10-hydroxycamptothecin (SN-38) alone and in the presence of organized media and also on its potential analytical applications. SN-38 displays native fluorescence in both lactone and carboxylate form, which has been the base for development of two spectrofluorimetric methods, one for the lactone form (acidic media) and another for the carboxylate form (basic media). In an attempt to improve the understanding of SN-38, its interaction with several cyclodextrins and surfactants has been studied using spectrofluorimetry.

Fluorescent determination of Hg2+ in water and fish samples using a chemodosimeter based in a Rhodamine 6G derivative and a portable fiber-optic spectrofluorimeter.

A fluorimetric chemodosimeter (FC1), based on a Rhodamine 6G derivative, is proposed for the recognition of Hg(2+) ions in water and fish samples. The reagent shows a highly selective and sensitive reaction with Hg(2+), giving rise to strong fluorescence emission at 555 nm. The obvious color change of the solution from colorless to pink upon the addition of Hg(2+) demonstrates that FC1 can be used for "naked-eye" detection of Hg(2+) in water effluents.

Simultaneous fluorometric determination of chlorophylls a and B and pheophytins a and B in olive oil by partial least-squares calibration.

The resolution of quaternary mixtures of chlorophylls a and b and pheophytins a and b has been accomplished by partial least-squares (PLS) multivariate calibration, applied to the fluorescence signals of these pigments. The total luminescence information of the compounds has been used to optimize the spectral data set to perform the calibration. After preliminary studies, a method is described in acetone media, to avoid emulsions with the olive oil samples.