Identification of the major drivers of 'phenolic' taste in ... - GWRDC

AWRI: Identification Of The Major Drivers Of ‘Phenolic’ Taste In White Wines
A.3 Development of a Separation and Identification
Strategy for Phenolic Compounds in White Wine
by HPLC-DAD and HPLC-QTOF
A.3.1 Introduction
In order to identify and quantify the diverse ‘phenolic’ compounds found in white wine, an HPLC
technique suitable for migration to mass spectrometry was developed. With the express intention of
not discriminating against possible species present that might elicit taste sensations characterized by
the broad term ‘phenolic’, a SPE sample clean-up step was not considered appropriate. These
decisions meant the chosen method had to be highly selective and discriminatory. Sample preparation
was thus based only on removal of alcohol by rotary evaporation and centrifugation replaced filtration
to avoid adsorption onto filtration fibres.
Method development followed a path of column selection – based on separating the maximum
number of separate peaks – and then mobile phase optimization.
A.3.2 Material and Methods
Chemicals
All chromatographic solvents were HPLC grade and chemicals were analytical grade unless otherwise
stated. Water was obtained from a Milli-Q Academic (Millipore, France) purification system using a
“Quantum” cartridge. methanol, acetonitrile (LiChrosolv, Merck, Germany), formic acid (98% v/v
Emsure, Merck, Germany) and trifluoroacetic acid (100% v/v Thermo, IL) were purchased from
Rowe Scientific (Lonsdale, SA, Australia). Polyphenolic standards were purchased from Sigma-
Aldrich or Extrasynthèse (France).
Wine Samples
Experimental wine was made at the Hickinbotham-Roseworthy Wine Science Laboratory using
established protocols. For the purposes of method development, a 2009 Riesling and a 2009
Chardonnay wine, made from the hard pressings juice fractions, was used throughout.
Preparation of Wine Samples
White wine samples were prepared by first removing alcohol by rotary evaporation (Heildorf,
Germany) with a water bath temperature