COLLABORATIVE ANALYSIS OF WHEAT, OATS, AND BARLEY FOR THIAMINE AND RIBOFLAVIN

In the analysis of wheat, oats, and barley for thiamine and riboflavin by three collaborating laboratories an attempt was made to reduce interlaboratory differences to a minimum by the establishment of a standardized procedure. The thiochrome and fluorometric methods were used for the thiamine and riboflavin determinations respectively. It was apparent that even after steps had been taken to standardize the assay procedures, small but consistent and significant interlaboratory errors existed. Calculations indicate that differences of the order of 10 to 12% in mean assay values were necessary before samples could be considered different with respect to their thiamine or riboflavin content.