Various methods were compared for the recovery of phenolic compounds from sweet orange. The need for careful consideration of sample preparation was demonstrated. In the case of cinnamic acids, hydroxide-treatment was essential to liberate the bound acids. Ferulic acid was the predominant phenol in alkali-treated extracts. Positive and negative ion electrospray ionisation mass spectra were systematically investigated for a range of phenols. Detection limits were significantly lower in negative ion than in positive ion mode. However, positive ion mode provided additional structural information for many of the compounds.
- Mass spectrometry
- Sample preparation