Immunoassays chromatographic

The utilization of lAC in analytical methods has received increasing retention in recent years [23,24], Of particular interest is the use of immobilized antibody columns in performing immunoassays, a technique known as a chromatographic immunoassay or flow-injection immunoassay. This approach has already been reported in a number of formats such as those involving simple analyte adsorption/desorption, sandwich immunoassays, competitive binding immunoassays, and multianalyte methods (see Figure 13,9) [23,24,73,74], Typical advantages of these methods include decreased analysis times and improved precision versus manual immunoassays. 

Hage, D.S. and Nelson, M.A., Chromatographic immunoassays, Anal. Chem., 73, 198A-205A, 2001. 

Osikowicz G, Beggs M, Brookhart P, et al. One step chromatographic immunoassay for qualitative deter-... 

Stone, J.A., and Soldin, S.J. (1988) Improved liquid chromatographic/immunoassay of digoxin in serum. Clinical Chemistry, 34, 2547 2551. 

Hage DS and Nelson MA (2001) Chromatographic immunoassays. Analytical Chemistry 73 198A-205A. 

Source From Chromatographic immunoassays, in Anal. Chem. " ... 

An alternative format for a chromatographic immunoassay is the displacement competitive binding immunoassay. In this format, the lAC column is first saturated with the labeled analogue, followed by application of sample to the column. As the analyte travels through the column, it is able to bind to any antibody sites that are momentarily unoccupied by the label as the analyte and antibodies undergo local dissociation and reassociation. This situation results in competition between the analyte and the label... 

Fig. 3 Typical scheme for a chromatographic competitive binding immunoassay. This particular example is for the simultaneous format. Source From Chromatographic Immunoassays, in Handbook of Affinity Chromatography...

A variety of detection schemes have been used with chromatographic immunoassays. The detection can be based on chemical tags that act as chromophores, fluOTO-phores, chemiluminescent agents, or electrochemically active species. Enzymes like (3-galactosidase, alkaline phosphatase, and horseradish peroxidase have also been employed as labels to generate products for detection by absorbance, fluorescence, chemiluminescence, electrochemical, or thermometric measurements. Liposomes, radiolabels, and bioassays have also been used for detection in chromatographic immunoassays. " ... 

Moser, A.C. Hage, D.S. Chromatographic Immunoassays. In Handbook of Affinity Chromatography, 2nd Ed. Taylor Francis New York, 2006 Chapter 29. 

Chromatographic immunoassays are not mentioned here in detail because they do not lead to a chromatographic separation of analytes. They constitute a special method for performing an immunoassay, i.e., to separate bound and free reagent species. 

FIGURE 1.2 Chromatographic immunoassay based on a sandwich, or two-site immu-nometric, format. 

Zolotarjova N, Boyes B, Martosella J. Immunoaffinity depletion of high-abundant proteins for proteomic sample preparation. In Smqkal GB, Lazarev A, editors. Separation methods in proteomics. Boca Raton, FL CRC Press 2006. p. 63—79. Moser AC, AC, Hage DS, DS. Chromatographic immunoassays. In Hage DS, editor. Handbook of affinity chromatography. 2nd ed. Boca Raton, FL CRC Press 2005. p. 789-836. 

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