Determination of oxygen heterocyclic components in citrus products by HPLC with UV detection.

The study of oxygen heterocyclic compounds (coumarins, psoralens, polymethoxylated flavones) in natural matrices such as citrus oils is not easy due to the difficulty of obtaining standards at the required level of purity and the diversity of structures present in each kind of sample. In this work, standards were either isolated by preparative LC methods from citrus oils or synthesized, then characterized by their physicochemical parameters and spectroscopic techniques, and further used for qualitative and quantitative calculations in citrus essential oils and products made with them (Earl Grey tea, liquors, juices). An HPLC method using an innovative partially porous particle HPLC column enabled baseline separation of all analytes. The method developed was validated in terms of detection limit, quantitation limit, linearity, and precision as repeatability and intralaboratory reproducibility.