Acetonitrile precipitation has been carried out as an investigative method for separating small from high molecular mass proteins. The separation has been visualized on a 1-D gel electrophoresis. Acetonitrile helps drive the proteins out of solution, to precipitate them. It is expected that small proteins will remain in the supernatant while big proteins precipitate out. Visualization of the purified cytosolic extract, the precipitate and the supernatant clearly show enrichment for small molecular mass proteins in the supernatant. In addition, the high molecular mass proteins in the non-precipitated cytosolic extract are enriched in the precipitate. This has proven to be a good method for enrichment of small molecular mass proteins. This method can be combined with protein separation and or identification methods in future experiments to effectively identify proteins with high accuracy. In addition, in-gel digestion (after acetonitrile precipitation) combined with mass spectrometry can further help identify small molecular mass proteins.