# Immunoaffinity chromatography

Immunoaffinity chromatography (IAC) is a liquid chromatography method in which the stationary phase is an antibody or antibody-related reagent, used to selectively capture and purify a target biomolecule from a complex mixture. It is a subcategory of affinity chromatography and the most common form of bioaffinity chromatography.<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup><sup> • </sup><sup>[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC7584770/)</sup><sup> • </sup><sup>[3](https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1075&context=chemistryhage)</sup>

| Key fact | Value |
|---|---|
| Stationary phase | Immobilized antibody or antibody-related ligand<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup> |
| Binding conditions | Neutral pH 7.0–7.4; equilibrium constants typically \( 10^{6} \)–\( 10^{12}\ \mathrm{M}^{-1} \)<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup> |
| Common elution | Low pH (1–3), chaotropes (1.5–8 M), competitive elution<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup> |
| Typical purification | Greater than 1000-fold, with ≥90% activity recovery<sup>[4](https://cdn.intechopen.com/pdfs/33050/InTech-Immunoaffinity_chromatography_a_review.pdf)</sup><sup> • </sup><sup>[5](https://experiments.springernature.com/articles/10.1385/1-59259-742-4:103)</sup> |
| Column reuse | 100 or more cycles, depending on impurity load<sup>[5](https://experiments.springernature.com/articles/10.1385/1-59259-742-4:103)</sup> |
| Main variants | Immunoextraction, immunodepletion, chromatographic immunoassays, peptide immunoaffinity capture (SISCAPA)<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup><sup> • </sup><sup>[6](https://www.sciencedirect.com/science/article/pii/S0003267021005407)</sup> |

## How it works

The immobilized antibody binds its antigen under physiological conditions, pH 7.0–7.4, where antibody–antigen equilibrium constants usually fall between \( 10^{6} \) and \( 10^{12}\ \mathrm{M}^{-1} \).<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup> Binding arises from electrostatic and hydrophobic interactions, van der Waals forces, and hydrogen bonding between the antigen and the antibody's binding site.<sup>[7](https://experiments.springernature.com/articles/10.1007/978-1-59745-324-0_5)</sup> Because these constants are so high, the antigen is effectively irreversibly retained while the sample passes through, and isocratic elution is generally not feasible unless a deliberately low-affinity antibody (\( K_{\mathrm{a}} < 10^{6}\ \mathrm{M}^{-1} \)) is used.<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup>

For quantitative capture with low nonspecific background, an antibody affinity of at least \( 10^{8}\ \mathrm{M}^{-1} \) and about two hours of antigen–antibody contact are recommended.<sup>[4](https://cdn.intechopen.com/pdfs/33050/InTech-Immunoaffinity_chromatography_a_review.pdf)</sup> Binding is reversed by changing the mobile phase so that desorption is favored: a step decrease in pH is the most common approach, and chaotropic salts or competitive agents are alternatives.<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup><sup> • </sup><sup>[8](https://b3p.it.helsinki.fi/download/GE_Protein_Purification_Handbooks/Affinity_Chromatography_Handbook.pdf)</sup>

## How it is done

**Coupling the antibody.** The classic support is CNBr-activated Sepharose, a cheap and fast covalent method; a working scale is 1 ml of slurry derivatized with 5 mg of antibody.<sup>[4](https://cdn.intechopen.com/pdfs/33050/InTech-Immunoaffinity_chromatography_a_review.pdf)</sup> Amine-reactive activations include N,N'-carbonyldiimidazole, cyanogen bromide, N-hydroxysuccinimide, and tresyl or [tosyl chloride](https://www.edgepedia.org/tosyl-chloride).<sup>[9](https://pmc.ncbi.nlm.nih.gov/articles/PMC4820777/)</sup> Because random coupling through lysines can point the binding site away from the mobile phase, oriented methods are preferred for scarce antibodies, such as oxidized Fc carbohydrate residues reacted with [hydrazide](https://www.edgepedia.org/hydrazide)- or amine-containing supports, free Fab sulfhydryls on thiol-reactive supports, or reversible attachment through Protein A/G followed by cross-linking.<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup><sup> • </sup><sup>[4](https://cdn.intechopen.com/pdfs/33050/InTech-Immunoaffinity_chromatography_a_review.pdf)</sup><sup> • </sup><sup>[9](https://pmc.ncbi.nlm.nih.gov/articles/PMC4820777/)</sup>

**Loading, washing, eluting.** A standard single-step protocol uses 25 mM Tris-HCl pH 8.0 with 300 mM NaCl as binding buffer, a two- to fivefold molar excess of antibody over target, overnight incubation at 4 °C, washing with 10–25 column volumes, and elution with 100 mM glycine pH 2.7 collected in fractions; each milliliter of eluate is neutralized immediately with 200 µl of 1 M Tris-HCl pH 9.0.<sup>[10](https://doi.org/10.1016/bs.mie.2014.11.006)</sup> Columns are stored as a 50% PBS slurry at 4 °C.<sup>[10](https://doi.org/10.1016/bs.mie.2014.11.006)</sup>

## Origin

The earliest affinity-type separation involved binding of α-amylase to insoluble starch.<sup>[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC7584770/)</sup> [Immunoprecipitation](https://www.edgepedia.org/immunoprecipitation) appeared in the 1930s as a tool for antibody characterization and purification.<sup>[3](https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1075&context=chemistryhage)</sup> Haptens were coupled by diazo chemistry to chicken erythrocyte stroma to isolate antibodies.<sup>[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC7584770/)</sup>

Antibody bound to modified cellulose as an immunospecific adsorbent of antigens was reported by A.T. Jagendorf, A. Patchornik, and M. Sela in 1963 in Biochimica et Biophysica Acta.<sup>[11](https://doi.org/10.1016/0006-3002%2863%2990913-2)</sup> Two later advances made modern IAC possible: beaded agarose, and the cyanogen bromide immobilization method described by Porath, Axén, and Ernback in 1967 in Nature.<sup>[3](https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1075&context=chemistryhage)</sup><sup> • </sup><sup>[12](https://doi.org/10.1038/2151491a0)</sup>

In 1968, P. Cuatrecasas, [Meir Wilchek](https://www.edgepedia.org/meir-wilchek), and [Christian B. Anfinsen](https://www.edgepedia.org/christian-b-anfinsen) combined beaded agarose with CNBr coupling to immobilize nuclease inhibitors and purify nucleases in the [Proceedings of the National Academy of Sciences](https://www.edgepedia.org/proceedings-of-the-national-academy-of-sciences); this paper was the first to use the name "affinity chromatography".<sup>[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC7584770/)</sup><sup> • </sup><sup>[13](https://doi.org/10.1073/pnas.61.2.636)</sup> Cuatrecasas and Anfinsen reviewed the method in the 1971 Annual Review of Biochemistry,<sup>[14](https://doi.org/10.1146/annurev.bi.40.070171.001355)</sup> and Antibodies attached to agarose were used for isolating modified peptides, an early IAC example.<sup>[2](https://pmc.ncbi.nlm.nih.gov/articles/PMC7584770/)</sup>

## Variants

**Immunoextraction** uses the antibody column to remove a specific analyte or group of analytes from a sample before a second analytical method; columns can be run offline or placed online with HPLC, MS, CE, or GC–MS, and large sample volumes can be applied to concentrate the analyte.<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup><sup> • </sup><sup>[9](https://pmc.ncbi.nlm.nih.gov/articles/PMC4820777/)</sup> When IAC is combined with silica or monolithic HPLC supports, the format is called high performance immunoaffinity chromatography (HPIAC).<sup>[15](https://pmc.ncbi.nlm.nih.gov/articles/PMC3346860/)</sup>

**Immunodepletion** is the inverse operation: an antibody column removes high- and mid-abundance proteins so that low-abundance components pass through for analysis.<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup> Multi-component immunoaffinity subtraction chromatography (IASC), reported by Rembert Pieper and colleagues in 2003 in PROTEOMICS, pooled antibody-coupled matrices to remove up to ten high-abundance plasma proteins in one step.<sup>[16](https://doi.org/10.1002/pmic.200390057)</sup> Commercial depletion columns based on this principle followed, including Agilent's MARS, Beckman Coulter IgY12, and Sigma-Aldrich IgY14 columns.<sup>[17](https://pmc.ncbi.nlm.nih.gov/articles/PMC3261331/)</sup><sup> • </sup><sup>[18](https://www.osti.gov/pages/servlets/purl/1251560)</sup>

**Chromatographic immunoassays** use the antibody column itself as the recognition element in an LC format.<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup> **Peptide immunoaffinity capture** operates after proteolysis: SISCAPA (Stable Isotope Standards and Capture by Anti-Peptide Antibodies) uses antibodies against proteotypic peptides with stable isotope-labeled standards for quantification, and multiplex immuno-MRM assays now determine more than 60 targets.<sup>[6](https://www.sciencedirect.com/science/article/pii/S0003267021005407)</sup>

## Applications

IAC is used for selective purification of proteins and for sample clean-up before analysis of foods for mycotoxins, veterinary drug residues, pesticides, and environmental contaminants, and it has been coupled with HPLC, GC, MS, and CE.<sup>[4](https://cdn.intechopen.com/pdfs/33050/InTech-Immunoaffinity_chromatography_a_review.pdf)</sup> In bioanalysis, antibodies on beads captured low-level protein doping agents from urine before LC-MS as early as the 1990s, detecting human chorionic gonadotropin at 25 mIU/mL (112.5 fmol/mL).<sup>[6](https://www.sciencedirect.com/science/article/pii/S0003267021005407)</sup> In high-performance formats, affinity extraction can remove targets in less than a few seconds, a feature used to measure free drug and hormone fractions in serum.<sup>[15](https://pmc.ncbi.nlm.nih.gov/articles/PMC3346860/)</sup> In bioprocessing, affinity capture is a standard first step for antibody therapeutics; as of 2007, 16 of 17 approved therapeutic monoclonal antibodies used Protein A affinity chromatography as the first capture step.<sup>[19](https://scialert.net/fulltext/?doi=jas.2012.1136.1141)</sup>

## Limitations and alternatives

**Random coupling wastes antibody.** With random covalent coupling, statistically two of three attachment events destroy antigen-binding capacity, and only one in three antibodies is optimally immobilized; oriented methods address this but Protein A/G-based beads are expensive, bind extraneous antibody, and their specificities are isotype-dependent.<sup>[4](https://cdn.intechopen.com/pdfs/33050/InTech-Immunoaffinity_chromatography_a_review.pdf)</sup>

**Elution stresses the product and the column.** Low pH 2.0–2.5 is the elution method of choice because it disrupts ionic and hydrogen bonds, but denaturing agents (8 M urea, 6 M guanidinium hydrochloride) and chaotropic salts (3 M sodium thiocyanate, magnesium chloride) can damage labile proteins and shorten column lifetime; chaotropes should be avoided when possible because they are likely to denature the eluted protein.<sup>[4](https://cdn.intechopen.com/pdfs/33050/InTech-Immunoaffinity_chromatography_a_review.pdf)</sup><sup> • </sup><sup>[8](https://b3p.it.helsinki.fi/download/GE_Protein_Purification_Handbooks/Affinity_Chromatography_Handbook.pdf)</sup> Mild alternatives include basic pH 9 elution, competitive small molecules, 1 M NaCl, or high propylene glycol concentrations.<sup>[10](https://doi.org/10.1016/bs.mie.2014.11.006)</sup> Alkaline elution cannot be used with silica or glass HPIAC supports, which are unstable above pH 8.0.<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup>

**Capacity decay and nonspecific loss.** Organic modifiers such as methanol decrease column capacity through denaturation whose kinetic reversal can take a few days.<sup>[1](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)</sup> Reducing agents cannot be used at any step because they reduce the antibody's disulfide bonds and diminish activity.<sup>[10](https://doi.org/10.1016/bs.mie.2014.11.006)</sup> In immunodepletion, significant nonspecific or specific loss of low-abundance proteins is a key caveat, especially for the SuperMix system with its large number of different antibodies.<sup>[18](https://www.osti.gov/pages/servlets/purl/1251560)</sup>

**Alternatives.** Protein A and Protein G bind the Fc region of IgG, and Protein L binds the variable domains of certain kappa light-chain subtypes, such as human Vk1, Vk3, and Vk4, with binding depending on the antibody species and sequence, giving complementary antibody-capture media that do not recognize a specific antigen.<sup>[20](https://research.fredhutch.org/content/dam/research/hahn/methods/Affinity_Chromatography_Handbook-Antibodies.pdf)</sup> MEP HyperCel mixed-mode resin binds antibodies at physiological pH and elutes at mildly acidic pH as a gentler alternative to Protein A chromatography, which requires strong acid elution that can denature antibodies and cause loss of potency.<sup>[21](https://mdpi-res.com/d_attachment/antibodies/antibodies-12-00015/article_deploy/antibodies-12-00015-v2.pdf?version=1677068652)</sup>

## References

1. [Immunoaffinity chromatography: an introduction to applications and recent developments (Hage et al., Bioanalysis 2010)](https://pmc.ncbi.nlm.nih.gov/articles/PMC2903764/)
2. [Affinity Chromatography: A Review of Trends and Developments over the Past 50 Years](https://pmc.ncbi.nlm.nih.gov/articles/PMC7584770/)
3. [Affinity Chromatography: A Historical Perspective (Hage & Matsuda, Methods in Molecular Biology, 2015)](https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1075&context=chemistryhage)
4. [Immunoaffinity Chromatography: A Review (IntechOpen)](https://cdn.intechopen.com/pdfs/33050/InTech-Immunoaffinity_chromatography_a_review.pdf)
5. [Immunoaffinity Chromatography of Proteins (Gallant, Methods in Molecular Biology)](https://experiments.springernature.com/articles/10.1385/1-59259-742-4:103)
6. [Affinity capture in bottom-up protein analysis – proteolytic peptide capture using antibodies and MIPs (Analytica Chimica Acta)](https://www.sciencedirect.com/science/article/pii/S0003267021005407)
7. [Antibody Purification: Affinity Chromatography – Protein A and Protein G Sepharose (Methods in Molecular Biology)](https://experiments.springernature.com/articles/10.1007/978-1-59745-324-0_5)
8. [Affinity Chromatography Principles and Methods Handbook (GE Healthcare/Cytiva)](https://b3p.it.helsinki.fi/download/GE_Protein_Purification_Handbooks/Affinity_Chromatography_Handbook.pdf)
9. [Chromatographic immunoassays: strategies and recent developments in the analysis of drugs and biological agents](https://pmc.ncbi.nlm.nih.gov/articles/PMC4820777/)
10. [Immunoaffinity Purification of Proteins (Kavran & Leahy, Methods in Enzymology, 2015)](https://doi.org/10.1016/bs.mie.2014.11.006)
11. [Use of antibody bound to modified cellulose as an immunospecific adsorbent of antigens (Biochimica et Biophysica Acta, 1963)](https://doi.org/10.1016/0006-3002%2863%2990913-2)
12. [JERKER PORATH, ROLF AXÉN, SVERKER ERNBACK (1967). Chemical Coupling of Proteins to Agarose. Nature.](https://doi.org/10.1038/2151491a0)
13. [P Cuatrecasas, M Wilchek, C B Anfinsen (1968). Selective enzyme purification by affinity chromatography.. Proceedings of the National Academy of Sciences.](https://doi.org/10.1073/pnas.61.2.636)
14. [P Cuatrecasas, C B Anfinsen (1971). Affinity Chromatography. Annual Review of Biochemistry.](https://doi.org/10.1146/annurev.bi.40.070171.001355)
15. [Pharmaceutical and biomedical applications of affinity chromatography (Hage et al., 2012)](https://pmc.ncbi.nlm.nih.gov/articles/PMC3346860/)
16. [Rembert Pieper and colleagues (2003). Multi‐component immunoaffinity subtraction chromatography: An innovative step towards a comprehensive survey of the human plasma proteome. PROTEOMICS.](https://doi.org/10.1002/pmic.200390057)
17. [IgY14 and SuperMix immunoaffinity separations coupled with LC-MS for human plasma proteomics biomarker discovery](https://pmc.ncbi.nlm.nih.gov/articles/PMC3261331/)
18. [Contributions of immunoaffinity chromatography to deep proteome profiling of human biofluids](https://www.osti.gov/pages/servlets/purl/1251560)
19. [Comparison of Binding Capacity and Affinity of Monoclonal Antibody towards Different Affinity Resins (Journal of Applied Sciences)](https://scialert.net/fulltext/?doi=jas.2012.1136.1141)
20. [Affinity Chromatography Handbook, Vol. 1: Antibodies (Cytiva)](https://research.fredhutch.org/content/dam/research/hahn/methods/Affinity_Chromatography_Handbook-Antibodies.pdf)
21. [Non-Affinity Purification of Antibodies (Antibodies, 2023)](https://mdpi-res.com/d_attachment/antibodies/antibodies-12-00015/article_deploy/antibodies-12-00015-v2.pdf?version=1677068652)

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*Topic: Encyclopedia › Life and health › Biological foundations › Biochemistry and metabolism › Biochemistry field and methods › Biochemical methods and techniques › Detection methods and analytical reactions*

*Initially written Sep 29, 2026 · Edited: Oct 15, 2026*

*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*

License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license