DisplayTitle

Quantitation and Reproducibility Problems in Reversed-Phase and Size-Exclusion HPLC Analyses of Wheat Proteins¹

¹Presented in part at the Annual Meeting of the American Association of Cereal Chemists, San Diego, CA, October 12–16, 1997. ²National Center for Agricultural Utilization Research, Biomaterials Processing Research, USDA, Agricultural Research Service, 1815 N. University Street, Peoria, IL 61604-3902. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable. ³Corresponding author. Telephone: 309/681-6360. Fax: 309/681-6685.

Reversed-phase (RP-) and size-exclusion (SE-) high-performance liquid chromatography have become important methods for rapid identification of wheat and other cereal cultivars and for revealing quality differences. Accuracy and reproducibility are essential for good results. Due to recent changes in these methods, however, such as using smaller columns, lower flow rates, and smaller samples, small procedural errors become more critical for final results. We therefore further studied the causes and magnitude of problems involving quantitation and reproducibility in RP- and SE-HPLC analyses of wheat proteins. Because of potential problems with protein adsorption to stainless steel system components, we modified systems to contain, insofar as possible, all plastic-type components. Other potentially major problems included weighing flour samples, achieving accurate solvent composition, and interpretation of data. Recognizing and dealing with these problems will enhance the accuracy, reproducibility, and usefulness of HPLC for varietal identification and quality prediction.