Simultaneous determination of proteins using an element-tagged immunoassay coupled with ICP-MS detection

We report a novel method that suggests that multiple proteins can be quantified simultaneously in complex biological samples. The use of distinguishable element-tagged antibodies allows discriminant detection with an Inductively Coupled Plasma Mass Spectrometer (ICP-MS), providing a sensitive and accurate means of determining the concentrations of specific proteins in complex mixtures. It is demonstrated that this method can be used to detect the levels of at least two target proteins at the same time, yielding a linear response to both proteins in a concentration range of 2-100 ng mL(-1) using a sample size of 0.5 mL.