Final answer:
The correct method to analyze fractions and measure the total amount of protein is the Bradford assay, which quantifies protein concentration through a colorimetric reaction.
Step-by-step explanation:
To analyze fractions and measure the total amount of protein in a sample, the Bradford assay is a suitable method. Unlike techniques such as gel electrophoresis and mass spectrometry which separate and characterize proteins, the Bradford assay quantifies the protein concentration. This assay relies on a color change produced by the binding of a dye to proteins, with the color intensity corresponding to protein concentration. By comparing the absorbance measurement to a standard curve, the total amount of protein can be quantified.