Development of a Solid-Phase Extraction Method for Determination of Pheophorbide a and Pyropheophorbide a in Health Foods by Liquid Chromatography

Abstract

A simple solid-phase extraction (SPE) method was developed for the liquid chromatography (LC) determination of pheophorbide (Phor) a and pyropheophorbide (Pyro) a in health foods such as chlorella, spirulina, etc. The food sample was extracted with 85% (v/v) acetone. The extract was acidified with hydrochloric acid and loaded on a C18 cartridge. After washing with water, Phor a and Pyro a were eluted with the LC mobile phase. Phor a and Pyro a were separated by isocratic reversed-phase LC and quantitated by fluorescence detection. The recoveries for spiked samples of chlorella and the extract were 87.1-102.0%. Commercial health foods (chlorella, spirulina, aloe, kale, Jews mallow, and green tea leaves) were analyzed using the SPE method. The values found for Phor a and Pyro a ranged from 2 to 788 microg/g and from <1 to 24 microg/g, respectively. There was no significant difference between the SPE method and the official method in Japan (spectrophotometry after liquid-liquid extraction). The advantages of the SPE method are the short extraction times, lack of emulsions, and reduced consumption of organic solvents compared with the official method in Japan. The SPE method is considered to be useful for the screening of Phor a and Pyro a in health foods.