Immunoaffinity column validation

Methods for analysing ochratoxin A were thoroughly reviewed in the previous report (Annex 1, reference 153). At that time, it was reported that validated analytical methods were available for the determination of ochratoxin A in maize, barley, rye, wheat, wheat bran, wholemeal wheat, roasted coffee, wine and beer. The best methods used LC following cleanup using immunoaffinity columns. Over 40 methods were reviewed. This review is limited to recent developments. 

Well-established and interlaboratory validated LC methods are published in the scientific specialized literature or as international standards. Those approved by the AOAC are mentioned in the standard procedures section (see also www.mycotoxins.org for a complete Hst of references). Their main features are described in Table 3. Most of these protocols include the use of immunoaffinity columns before LC analysis. 

Muscarella, M., Lo Magro, S., Palermo, C., and Centonze, D. 2007. Validation according to European Commission Decision 2002/657/EC of a confirmatory method for aflatoxin Ml in milk based on immunoaffinity columns and high performance liquid chromatography with fluorescence detection. Anal. Chim. Acta 594 257-264. 

Affinity chromatography techniques have shown less utility in analytical testing than in preparative separations for a variety of reasons, including cost and the difficulty of validating consistent operation as the column changes over time. Protein A affinity has been commonly used to quantitate the total antibody content of either ascites or cell culture fluids. To provide guidance in the development of a purification process, specific immunoaffinity resins are either available or can be readily prepared to quantitate the levels of unrelated protein contaminants. To rapidly determine what the active species in a mixture is, a monoclonal antibody that... 

---