ABSTRACT
A straightforward and versatile methodology for the extraction of volatile metabolites in biological samples from ruminants for gas chromatography analysis is proposed. The methodology was applied in the determination of multiclass metabolites (short-chain fatty acids, aldehydes, alcohols, ketones, esters, phenols, and sulfides) in different analytical matrices (rumen fluid, urine, and feces) collected from Holstein cows. The 24 multiclass volatile metabolites reported in the different biological samples and their respective concentrations were critically discussed in the context of digestive physiology. Most detected compounds are derived from the rumen and lower gut fermentation of carbohydrates, proteins, and lipids or their metabolism, being consistent with the prior state of the art. The proposed method also takes advantage of the already existing tools in animal nutrition laboratories, providing a novel methodological ground that can generate relevant bioanalytical information with a significant impact on ruminant's nutritional studies.
Subject(s)
Liquid-Liquid Extraction , Ruminants , Animals , Cattle , Chromatography, Gas , Fatty Acids, Volatile/analysis , MetabolomeABSTRACT
In this work, an analytical methodology for volatile carbonyl compounds characterization in green and roasted coffee beans was developed. The methodology relied on a recent and simple sample preparation technique, gas diffusion microextraction for extraction of the samples' volatiles, followed HPLC-DAD-MS/MS analysis. The experimental conditions in terms of extraction temperature and extraction time were studied. A profile for carbonyl compounds was obtained for both arabica and robusta coffee species (green and roasted samples). Twenty-seven carbonyl compounds were identified and further discussed, in light of reported literature, with different coffee characteristics: coffee ageing, organoleptic impact, presence of defective beans, authenticity, human's health implication, post-harvest coffee processing and roasting. The applied methodology showed to be a powerful analytical tool to be used for coffee characterization as it measures marker compounds of different coffee characteristics.
Subject(s)
Chemical Fractionation/methods , Chromatography, High Pressure Liquid/methods , Coffee/chemistry , Food Handling/methods , Tandem Mass Spectrometry/methods , Aldehydes/chemistry , Antioxidants/chemistry , Ketones/chemistry , VolatilizationABSTRACT
Introdução: As infecções oculares são um desafio constante na prática oftalmológica diária. Material e Métodos: Foram analisados 155 casos de infecções oculares supostamente bacterianas, atendidos nos serviços do Instituto/Fundação Hilton Rocha, de janeiro de 1996 a dezembro de 1999. Resultados: O quadro clínico predominante foi a conjuntivite (29,6 por cento), seguido pela blefarite (27,09 por cento) e úlcera de córnea (21,29 por cento). Nos casos de cultura positiva, os microorganismos mais comumente isolados foram o estafilococos epidermidis (48,12 por cento) e o estafilococos aureus (38,34 por cento). Dentre os agentes patológicos detectados, o estafilococos aureus foi o que apresentou maior resistência aos antibióticos utilizados na prática oftalmológica (41,18 por cento a ofloxacina). Conclusão: A análise laboratorial rigorosa e a escolha criteriosa dos medicamentos, muitas vezes com associação de drogas, são passos fundamentasis para o sucesso nestes casos.
