Simultaneous determination of ethanol and glycerol in wines by a flow injection-pervaporation approach with in parallel photometric and fluorimetric detection

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• 作者：Mataix ; E. ; Luque de Castro ; M.D.
• 关键词：Ethanol ; Glycerol ; Wine ; Flow injection ; Pervaporation ; Immobilised enzyme ; Photometry ; Fluorimetry
• 刊名：Talanta
• 出版年：2000
• 出版时间：March 6, 2000
• 年：2000
• 卷：51
• 期：3
• 页码：489-496
• 全文大小：91.6 K

文摘

A simultaneous method for the determination of ethanol and glycerol in wines based on the coupling of pervaporation-chemical derivatisation-photometric detection for ethanol and biochemical derivatisation-fluorimetric detection for glycerol is proposed. After separation by pervaporation the ethanol is collected in a K₂Cr₂O₇ acceptor stream and the Cr³⁺ formed is driven to the spectrophotometer and monitored at 600 nm. The determination of glycerol is based on its oxidation by oxidised β-nicotinamide adenine dinucleotide (β-NAD⁺) catalysed by glycerol dehydrogenase immobilised on controlled-pore glass, the reduced form of the coenzyme (NADH) being spectrofluorimetrically monitored (λ_ex=340 nm, λ_em=460 nm). The linear determination range is between 1–20 % for ethanol and 2–8 g l⁻¹ for glycerol, with RSDs 3 and 2 % , respectively. The method applied to red and white Spanish wines, compares well with the official methods for these analytes.