Tandem absorbance and fluorescence detection following liquid chromatography for the profiling of multiclass phenolic compounds in different winemaking products.

A liquid chromatography method coupling diode-array and fluorescence detectors (DAD and FLD, respectively) has been developed for the simultaneous quantification of 32 phenolic compounds (PCs) in winemaking products. With the combination of both detectors it was possible to determine phenolic acids, flavanols, flavonols, stilbenes and other PCs in the matrices under study. An excitation wavelength of 290 nm was selected and three different emission wavelengths (315, 360 and 400 nm) were recorded. The method provided detection and quantification limits (LODs and LOQs) within the ranges of 0.01-1.46 mg/L and 0.03-4.9 mg/L, respectively. The LODs and LOQs using FLD for flavanols, stilbenes and phenyl ethanol analogues were improved between 65 and 1000% as compared with DAD. The combination of DAD with FLD increased both, sensitivity and the ability to reduce interfering signals. The developed method was applied for the characterization of PCs of wines, bunch stems and grape canes.