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Resveratrol (3,5,4′-trihydroxystilbene) is a phytoalexin that belongs to the group of stilbenes, known to occur in grapes and consequently in grape products. Its presence in wine is an important qualitative parameter because of the several beneficial effects on human health. The aim of this work is the development of a high-performance liquid chromatographic (HPLC) method for the determination of trans resveratrol in wines, and comparisons between the results obtained by different detection techniques: UV-vis spectroscopy, fluorescence spectroscopy and mass spectrometry. Resveratrol is analysed on a C-18 column using gradient elution. The method permits direct injection of sample, revealing to be time-saving, overcoming the need of sample pre-treatment steps. Detection limits were 154.8 ng mL−1 by HPLC-UV, 118.0 ng mL−1 by HPLC-FL and 48.0 ng mL−1 by HPLC-MS. Trans resveratrol has been then quantified in a group of 52 wines derived from different Italian regions, cultivars and winemaking technologies by HPLC-UV.

Melatonin content in pharmaceutical products was quantitatively determined by capillary electrophoresis within 4 min. Sample preparation required the simple dissolution in water and filtration. An internal standard was used a linear relationship between melatonin concentration andR(melatonin corrected peak area/I.S. corrected area) was obtained, withr 2>0.998. Separations were carried out in coated capillaries with a borate running buffer. The method showed an high precision with a RSD value for migration times of 0.3% for intra-day and 1.4% for inter-day measures (n=48). For theR parameter RSD was 2.9% and refers to seven consecutive runs of the same sample on the same day. Two commercially available pharmaceutical products containg melatonin were analyzed. The method offers an easy and accurate routine option.

Some citrus essential oils were analyzed by HPLC with both microbore and standard columns in reversed and normal phase. Volatile and non-volatile fraction were investigated. In the non-volatile fraction some coumarins have been identified. Fractions are detected spectrophotometrically at 220 nm and 320 nm before and after evaporation of samples. Some components were also identified by LC/MS.