Chapter 10 - Electrophoretic Techniques

Abstract

Electrophoresis means the migration of charged molecules and particles under the influence of an electrical field. The electrophoretic mobility of charged molecules depends mainly on the pH and ionic strength of the buffer. Electrophoretic separations are carried out either in free solution (e.g., as in capillary and free flow systems) or in support matrices (e.g., agarose or polyacrylamide gels), and even complex mixtures can be resolved based on differences in charge and/or size of the molecules. Three basically different electrophoretic principles (i.e., zone electrophoresis, isotachophoresis, isoelectric focusing) are generally used; the analytes include mainly proteins, peptides, sugars, nucleic acids, and inorganic ions. Electrophoretic techniques are widely used in authentication of animal foods (e.g., dairy, meat, fish, and egg products) as well as plant foods (e.g., cereal grains, soy, fruits, and vegetables); areas of application include mainly the identification/differentiation of species, varieties, types, breeds, cultivars, or brands of different foodstuffs that have protected geographical status.