Determination of amino acids in diverse polymeric matrices using HPLC, with emphasis on agars and agaroses

Determination of amino acids in polymers with varying structure and charge was performed using vapor phase acid hydrolysis and subsequent precolumn de rivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC). Pe rcent load of neutral, cationic and anionic peptide-modified synthetic poly mers was accurately determined using this technique. Assay utility was show n for glycosaminoglycans and other sulfated polymers, neutral carbohydrate polymers such as agar, agarose, and cellulose, and polymers such as lipopol ysaccharide and deoxyribonucleic acid. The carboxylated and sulfated molecu les included chondroitin sulfate, hyaluronic acid, dermatan sulfate, and he parin, and the sulfated polymers included fucoidan, carrageenan, and dextra n sulfate, as examples. Assayed cumulative amino acid concentrations (i.e. protein levels) are reported, although amino acid distribution data was als o available from the analysis. Recovery was acceptable for the various comp ounds tested and did not correlate with structure. However, different sampl e sizes were necessary to achieve acceptable recovery, depending on the lev el of protein present in the matrix. While some matrices contained peaks in addition to the amino acids and amino sugars, they were not found to inter fere using the standard gradient separation. Assayed amino acid profiles we re compared for agaroses with differing electroendosmosis values and for ag ar samples from different parts of the globe. While the amounts of protein varied depending on source, the relative distribution of amino acids was ve ry similar across the agar samples surveyed. (C) 1999 Elsevier Science B.V. All rights reserved.