ASTM F2259-03 (2008) – Determining the Chemical Composition and Sequence in Alginate by 1H NMR
Alginate is a linear polysaccharide composed of mannuronate (M) and a-L-guluronate (G). The polysaccharide is characterized by the relative ratio of M/G, G-Content, and average length of blocks of G in the polymer. M and G are:
ASTM F2259 recounts the standard sample preparation and 1H NMR analysis that allows the following parameters to be calculated:
The 1H NMR spectra obtained on a typical alginate sample are show below:
Finally the peaks representing the individual M and G components and sequences are deconvoluted from the spectrum. The intensities obtained from the deconvolution are input into the excel spreadsheet shown above and the various ratios, M and G content and a series of diads and triads are calculated along with some G block length information. It is the block length information that often reveals telling differences between samples.
Process NMR Associates performs this analysis at a cost of $225 per sample. The samples, however, must be prepared by the customer using the methodology set forth in the test method.
Contact John Edwards of you are interested in performing this analysis, or call +1 (203) 744-5905[/vc_column_text][/vc_column][vc_column width=”1/2″][vc_column_text]
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