The present invention provides dual labeled protein standards useful for the simultaneous determination of the molecular weight of a subject protein as well as the relative mass (i.e., amount) of the subject protein present in an electrophoresis lane. The invention is also directed to methods suitable for the preparation of such dual labeled protein standards and to methods of using such dual labeled proteins to simultaneously determine the molecular weight and the relative amount of a subject protein. Further embodiments are directed to the use dual labeled protein standards to make a more accurate determination of the amount of a protein present in an electrophoresis lane. Yet further embodiments are directed to kits containing the presently described dual protein standards. Dual labeled protein standards made and used in accordance with the embodiments set forth herein may be used to simultaneously determine the molecular weight and the relative amount of a subject protein in real time.