Intralaboratory Validation of Cell-Free Translation Assay for Detecting Ricin Toxin Biological Activity
Abstract:A cell-free translation (CFT) assay for determining ricin biological activity was validated. The statistical data from the validation study showed a high level of precision within and between runs of the assay. The assay was specific for determining ricin biological activity in food-based matrixes and discriminated ricin from other ribosomeinactivating proteins. The mean bias (relative error) between measured ricin concentrations of 3 validation samples and their nominal concentrations was 1.1, 6.6, and 20.3, while the coefficient of variation (CV) was 14.1, 7.7, and 13.5, respectively, demonstrating good precision, accuracy, and linearity. The CVs of ricin concentrations in 2 ricin-containing samples calculated from a dilution series were <5 and <12, respectively, demonstrating very good parallelism. The analyte stability of ricin-containing samples stored for 1 month either at 4 or 20C, the stability of ricin stock solutions, and the results of assays executed by different analysts and using different luminometers were evaluated. The statistical validation data confirmed that the 4-parameter logistic equation, y = (a d)/[1 + (x/c)b] + d, provided an accurate representation of a sigmoidal relationship between the measured response and the observed ricin concentration for the CFT assay.
Document Type: Research Article
Affiliations: U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702-5011.
Publication date: 2007-09-01
More about this publication?
- The Journal of AOAC INTERNATIONAL publishes refereed papers and reviews in the fields of chemical, biological and toxicological analytical chemistry for the purpose of showcasing the most precise, accurate and sensitive methods for analysis of foods, food additives, supplements and contaminants, cosmetics, drugs, toxins, hazardous substances, pesticides, feeds, fertilizers and the environment available at that point in time. The scope of the Journal includes unpublished original research describing new analytical methods, techniques and applications; improved approaches to sampling, both in the field and the laboratory; better methods of preparing samples for analysis; collaborative studies substantiating the performance of a given method; statistical techniques for evaluating data. The Journal will also publish other articles of general interest to its audience, e.g., technical communications; cautionary notes; comments on techniques, apparatus, and reagents.
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