Ideally, any technology for detecting Host Cell Proteins (HCPs) should: (i) detect protein concentrations across a wide dynamic range, from very low to much higher concentrations of impurity proteins; (ii) track changes in HCP populations and concentrations throughout the entire bioprocess; (iii) simultaneously monitor and measure multiple protein analytes; and (iv) detect low concentration HCPs even in the presence of high concentrations of the target recombinant protein.