Ion Exchange Chromatography (IEC) - A gradient driven separation primarily based on the cost of the protein and its relative affinity for the chemical backbone of the column. Previous to reaching their pI, protein mobility also depends upon measurement, high-quality amino acids supplier conformation, steepness of pH gradient, and the voltage gradient. The protein may be eluted in a reducing salt gradient, with essentially the most hydrophobic proteins eluting from the column final. Two-dimensional Gel Electrophoresis - A type of electrophoresis during which proteins are separated first in one course by cost followed by a dimension separation within the perpendicular course.