Producing high quality two-dimensional electrophoretic gels of bacterial cell membrane proteins is challenging because of non-membrane protein impurities within cell membrane preparations and the intractability of membrane proteins for solubilisation. Incubation of cell membrane preparations with sodium carbonate solution enriches for cell membrane proteins by stripping away other loosely associated protein contaminants from membranes (e.g., ribosomes, elongation factors). With the aid of strong sample solubilising reagents compatible with two-dimensional electrophoresis (2-DE), many of the carbonate-enriched membrane proteins can be separated using standard 2-DE techniques.