Finding differentially expressed proteins is an important component in many areas of biological research. A common approach is to separate the proteins by chromatography or electrophoresis followed by identification using mass spectrometry. Two-dimensional electrophoresis is commonly employed as the electrophoretic method and enables very-high-resolution separations. In the mid 1990s, the term proteomics was coined to describe this research area, establishing an additional expression-based dimension to genomics.