Mixed total diet slurry as a prospective reference material

A total diet composite based on foods from the U.S. FDA Total Diet Study was investigated to assess its suitability as a slurry material as a candidate reference material in the form of a slurry. Results for the distribution of chlorine and sodium (overall variation 2% for Na and 3% for Cl) indicated no serious problems of sedimentation. Similarly determination of Co, Se, Rb, Sn, Fe and Zn covering an overall concentration (dry weight basis) range of 25 ng/g for Co to 33 μg/g for Fe and Zn, suggests that the homogeneity of the composite is reasonably good. However the operational steps adopted for this preliminary investigation were not optimal. Use of a high pressure diffusion type of approach adopted by the National Research Council of Canada in preparing the lobster hepatopancreas matrix (LUTS-1) should further improve the homogeneity characteristics of the slurry.