Article ID Journal Published Year Pages File Type
1242459 Talanta 2010 7 Pages PDF
Abstract

A sensitive sandwich type immunoassay has been proposed with the detection by inductively coupled plasma mass spectrometry (ICP-MS) in a single particle mode (time resolved analysis). The signal induced by the flash of ions (197Au+) due to the ionization of single Au-nanoparticle (Au-NP) label in the plasma torch can be measured by the mass spectrometer. The frequency of the transient signals is proportional to the concentration of Au-NPs labels. Characteristics of the signals obtained from Au-NPs of 20, 45 and 80 nm in diameters were discussed. The analytical figures for the determination of Au-labeled IgG using ICP-MS in conventional integral mode and single particle mode were compared in detail. Rabbit-anti-human IgG was used as a model analyte in the sandwich immunoassay. A detection limit (3σ) of 0.1 ng mL−1 was obtained for rabbit-anti-human IgG after immunoreactions, with a linear range of 0.3–10 ng mL−1 and a RSD of 8.1% (2.0 ng mL−1). Finally, the proposed method was successfully applied to spiked rabbit-anti-human IgG samples and rabbit-anti-human serum samples. The method resulted to be a highly sensitive ICP-MS based sandwich type immunoassay.

Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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