Discriminative Determination of Copper, Iron and Magnesium in Chlorophyll and Chlorophyllin Complexes and Their Contents in Foods

Abstract

A convenient discriminative determination of copper (Cu), iron (Fe), magnesium (Mg) in chlorophyll and chlorophyllin complexes was developed. Vegetable samples were extracted with ethanol, and chewing gum samples with n-butyl acetate, ethanol and water. The metal chlorophyll (Cu, Fe and Mg) and metal chlorophyllin (Cu, Fe and Mg) in the extracts were purified and separated at either pH 8-9 or pH 5-6 by making use of partition chromatography with n-butyl acetate-ethanol-water (10:40:60). The metal in the discriminated chlorophyll and chlorophyllin was determined with a flame-type atomic absorption spectrometer.The recoveries of metal chlorophylls and chlorophyllins were as follows: Cu chlorophyll, 88%; Fe chlorophyll, 64%; Mg chlorophyll, 79% and Cu chlorophyllin, 87%; Fe chlorophyllin, 80%; Mg chlorophyllin, 87%.We have carried out a survey on metal chlorophyll and chlorophyllin in 36 vegetables and 5 chewing gums and found that some of them contained metal chlorophylls and chlorophyllins at the level of 0.1ppm or over.