Measurement of Iron in Egg Yolk: An Instrumental Analysis Experiment Using Biochemical Principles

The generally accepted method to determine iron content in food is by acid digestion or dry ashing and subsequent flame atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry. We have developed an experiment that chemically extracts the iron from an egg yolk and quantifies it using UV–vis absorption spectrophotometry. Only the yolk of an egg is used because it contains almost all of the iron in an egg and the extraction is more efficient than with the whole egg. The experiment is suitable for the instrumental analysis portion of the analytical chemistry course and serves to demonstrate to the students the chemical and biochemical principles that can be used for the extraction of a mineral from a complex organic matrix.