Scale down quick, easy, cheap, effective, rugged and safe method for the determination of 3-alkyl-2-methoxypyrazines in wines by gas chromatography-mass spectrometry

FONTANA, A.; BOTTINI, R.

Honolulu

Congreso; 2015 International Congress of Pacific Basin Societies (Pacifichem 2015); 2015

American Chemical Society

Alkyl methoxypyrazines (MPs) are nitrogen-containing heterocyclic molecules that are aroma active compounds found in many wine varietals. These compounds can be of whichever grape-derived nature or introduced into wines via microorganisms contaminating the berries. From berries, MPs are transferred into wine, contributing to various green-herbaceous aroma notes. Albeit their origin, MPs can have either a beneficial role for wine quality, contributing to the specificity of certain wine varietals (Cabernet sauvignon, Cabernet franc, Sauvignon blanc) or a detrimental role, particularly at higher concentrations, resulting in overpowering green, unripe and herbaceous notes. The sensory detection thresholds of MPs are very low and in wines at concentrations lower than 40 ng L-1. Due to the relevant organoleptic impact of MPs on wine quality and authenticity at very low levels, the development of analytical methodologies for the sensitive determination of them in wine samples is a subject of growing interest.The aim of this work was the development and validation of a simple, fast, efficient and robust method for the quantification of MPs in wines using a quick, easy, cheap, effective, rugged and safe (QuEChERS) approach followed by GC-MS determination. The proposed method includes a double step analytical technique based on single-phase solvent extraction with 500 µL toluene and salting-out partitioning, followed by a miniaturized dispersive solid-phase extraction (DSPE) with PSA to remove the remaining matrix co-extractives. Determination by GC-MS with single ion recording (SIR) mode and sample preparation conditions were optimized in order to maximize the yield, sensitivity and selectivity. The performance of the proposed methodology was evaluated in terms of limits of quantification, absolute recoveries, precision and linear working range. Besides, the developed method was checked for the determination of MPs in wines of different grape varieties.