Istituto Agrario di San Michele all'Adige (IASMA - Fondazione ...

at 25°C. The injection volume is 10μL. Routinely,
only 4 electrodes are used, specifi cally at 340, 380,
550 and 800mV versus Pd/H2 reference electrode,
the dominant channels being at 380mV for 4-VG and
4-EG, and at 550mV for 4-VP and 4-EP. The use of
eight electrodes (280, 340, 380, 430, 490, 550, 650,
800mV) makes it possible to resolve the few cases
where 4-VG can partially co-elute.
HPLC- FLD method
The wine sample is fi ltered as reported above. Analysis
is carried out with HPLC equipped with a fl uorimetric
detector (excitation at 225nm; emission at
320nm). Isocratic separation is performed with the
aformentioned eluent, on a Zorbax Eclipse Plus C18
column (4.6mm x 50mm, 1.8μm particle size; 25°C),
with a fl ow rate of 1.5mL min-1. The injection volume
is 10μL.
Assessing volatile phenol risks in wine
In order to assess the actual extent of volatile phenol-related
risk in the wines available on the market,
the methods were applied to the analysis of
Advantages of the HPLC-ED method
The HPLC-ED method accurately analyses 4-ethylphenol, 4-ethylguaiacol, 4-vinylphenol, and 4-vinylguaiacol
in wine as well as in beer. Compared to the previously published methods, the proposed procedure offers
important advantages as it does not require sample preparation and performs chromatographic separation
in roughly 15 minutes.
The method is linear up to concentrations of 2000μg L-1 and precise (RSD < 3%). Limits of detection are low
(1–3μg L-1) and suitable for analytical requirements in the oenological fi eld. In contrast to the electrochemical
approach above, the HPLC-FLD method specifi cally quantifi es 4-ethylphenol, carrying out chromatographic
separation in less than 5 minutes. It is linear up to 2000μg L-1, with RSD 426μg) which could potentially
affect wine aroma.
We observed a trend towards higher concentrations
in DOC wines (median = 400μg) than in table wines
(230μg). This apparent contradiction with the typically
higher quality image of the former must be
traced back to the limited use of barrique ageing
(and relative “Brett” pollution) for lower priced
wines.