Classification of wines from five Spanish origin denominations by aromatic compound analysis.

Wine is a complex matrix in which aroma compounds play an important role in the characterization of the flavor pattern of a given wine. Twelve volatile compounds were determined in 244 samples of Spanish red wines from different denominations of origin: Rioja, Navarra, Valdepeñas, La Mancha, and Cariñena. The samples were analyzed by GC using headspace solid-phase microextraction.

A thorough study on the use of quantitative 1H NMR in Rioja red wine fermentation processes.

In this study, we focused our attention on monitoring the levels of important metabolites of wine during the alcoholic and malolactic fermentation processes by quantitative nuclear magnetic resonance (qNMR). Therefore, using (1)H NMR, the method allows the simultaneous quantification of ethanol, acetic, malic, lactic, and succinic acids, and the amino acids proline and alanine, besides the ratio proline/arginine through fermentation of must of grapes corresponding to the Tempranillo variety. Each (1)H NMR spectrum gives direct and visual information concerning these metabolites, and the effectiveness of each process was assessed and compared by carrying out analyses using infrared spectroscopy to ethanol and acetic acid.

Bioaerosols chemometric characterization by laser-induced fluorescence: air sample analysis.

A laser-induced fluorescence (LIF) system was optimized using a solution of Micrococcus luteus in ethanol/water 50% (v/v) to obtain spectra in the gas phase of 46 bioaerosols. Experimental designs such as Plackett-Burman and factorial design were applied. The fluorescence spectra were treated chemometrically by principal component analysis, linear discriminant analysis and hierarchical cluster analysis to classify the microorganisms according to family, morphology and gram.

Simultaneous determination of arsenic, antimony, selenium and tin by gas phase molecular absorption spectrometry after two step hydride generation and preconcentration in a cold trap system.

A cold trap system for the simultaneous determination of arsenic, antimony, selenium and tin by continuous hydride generation and gas phase molecular absorption spectrometry is described. The hydride generation is carried out in two steps; first, tin hydride is generated at low acidity and second, arsenic, antimony and selenium hydrides are formed at higher acidity. All the hydrides are collected in a liquid nitrogen cryogenic trap and transported to the flow cell of a diode array spectrophotometer, where molecular absorption spectra are obtained in the 190-250 nm range.

Bacteria spectra obtained by laser induced fluorescence.

Laser-induced fluorescence technique (LIF) is described for getting bacteria spectra in the liquid phase. An excimer laser pumping a dye-laser and a doubly frequency laser have been used, exciting the bacteria to 290 nm, and using a monochromator, 600 lines/mm grating, with a CCD to measure and obtain the fluorescence spectra. In this study, a laser induced fluorescence system to measure certain bioaerosols (bacteria) was optimised.