“…Multilabel methods often need several labels, such as enzyme, fluorescence dye, radioisotope and quantum dot, which limits their application (Zhang et al, 2007;Wu et al, 2007a;Tang et al, 2009a,b,c;Tang and Ren, 2008;. Electrochemical multiple immunoassays, especially potentiometric assays, have many advantages including high-throughput systems, low assay cost, label-free, and simple instrumentation that enables device miniaturization and easy signal quantification (Wu et al, 2007b;Tang et al, 2007).…”