Protein Identification

All service contracts are performed through a LTQ-Oribitrap manufactured by Thermo Fisher Scientific.  The detection limit of proteins from SDS-PAGE gel bands through the use of LC/MS/MS is in the femtomole range or on a weight basis in the low nanogram range (1-5ng). This is also very similar to the detection limit of proteins stained with silver and sypro ruby stains. Colloidal coommassie stains typically have detection limits between 10 and 20ng and coommassie brilliant blue has a detection limit near 50ng. The detection limits of these stains will be dependent on many variables such as the thickness of the gel and the width of the lanes. While the detection limit of protein staining is on a weight basis the detection limit of protein with the mass spectrometer is on a molar basis, therefore the higher the molecular weight, at the same mass, the higher the detection limit will be for the mass spectrometer.

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