AOAC SPDS Mid Year 2016

Challenges with Existing Methods • Kjeldahl, Dumas: not selective to protein; • True Protein Kjeldahl: non‐protein, nitrogen‐containing  compounds may precipitate or form complex with  precipitated protein • Amino Acid: Inaccurate quantitation due to variable  recovery of amino acids • Copper, Dye‐Binding: other constituents besides proteins  form complexes • Lack of Standards – Protein biosynthesis is expensive, time‐consuming, not robust – Proteins samples vary widely and usually include multiple proteins

Things to Consider • Should method address qualitative or quantitative aspect?   Or, both? • Should ranges be established for quantitative methods? • Are multiple methods required as part of orthogonal  approach due to complex nature? • How to define which proteins need to be analyzed, since  samples usually contain multiple proteins, and even the  same protein species can be diverse between samples? • How to overcome the challenge of obtaining adequate  reference material standards?