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 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 lkength 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.

Process NMR Associates Offers Testing, Consultation, and Support in Meeting Your Identity Testing, Laboratory Methodology, and Process Analytical Requirements for FDA DS CGMP Rule Compliance.

In conjunction with 21 CFR 111, the FDA’s Office of Nutrition, Labeling and Dietary Supplements has instituted the Dietary Supplement Current Good Manufacturing Practice Rule (DS GCMP Rule) and the Interim Final Rule effective December 2010. Laboratory compliance, including identity testing and analytical method protocols are now required for any manufacturer, packager, labeler or holder of dietary supplements without the previous exemption based on number of full time employees within the company. Smaller companies, typically without in-house laboratory and testing facilities, now need to obtain such services to meet the new compliance rules.

Process NMR Associates (PNA), the process analytical consulting company and analytical testing company with over 45 years of experience in the field of nuclear magnetic resonance spectroscopy (“NMR”) and organic spectroscopy (FTIR, NIR, ESR) is now offering expanded services for DS GCMP Rule compliance. As an example, The International Aloe Science Council (IASC), a trade association representing the global aloe vera industry, has selected Process NMR Associates, LLC (PNA) as its primary provider for Nuclear Magnetic Resonance (NMR) spectroscopic measurement of aloe vera. PNA’s services include measurement of aloe vera concentration, sacharride distributions, formulation ingredients, and, contaminant/degradation products, in aloe vera powders, whole leaf extracts, whole leaf and inner leaf gel concentrates, drink concentrates, and, ready to drink formulations. PNA’s NMR services are an integral part of the IASC certification and compliance program. “We are pleased to partner with Process-NMR Associates for providing analytical services related to the certification program,” said Devon Powell, Executive Director of the IASC. “PNA has demonstrated its capability to provide excellent analytical services in a timely manner to the organization and aloe vera industry at-large.”

Expanding analyses and methodologies beyond aloe vera include essential oil analyses, fish oils and omega-3 fatty acid analyses, herbal supplement characterization, adulteration monitoring, and, ingredient integrity analyses. It is PNA’s commitment to quality analytical services, sample analysis, reporting turnaround, and competitive pricing that enable us to provide value-added services to the dietary supplement market place.