4
should be as much as similar to the real sample. In the determination of oleuropein
the matrix test used was the corn oil which is substantially identical to extra virgin
olive oil except for the absence of phenols; fortifying this matrix with a known
amount of analyte and internal standard and submitting the sample to all the experimental steps, a value near the theoretical amount added should be obtained.
Accuracy values in the range 85–115% are generally accepted.
1.2.2 Assessment of Resveratrol Amount in Red Wine
The use of labelled internal standard, in conjunction with tandem mass spectrometry, represents a big improvement of analytical performances in the determination of
quality markers in food. On the other hands, there are cases in which combining this
two techniques may create some complications. The determination of resveratrol
performed by Di Donna et  al. [14] has been performed using the labelled
Fig. 1.2 High resolution
pseudomolecular ion signal
of OLP (A) and
d 3 -OLP (B)
G. Sindona and L. Di Donna