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CHON-002
Question
Response
General
AOAC Method Number:
CHON-002
Method Title:
Isotachophoretic Determination of Glucosamine and
Chondroitin Sulphate in Dietary Supplements, Czech Journal of
Food Science 31:55-65
Method Author(s):
Eliska Vaclavikova and Frantisek Kvasnicka
Reviewer Name:
Kelly Reins
Summary of Method
Capillary isotachophoretic method for the determination of
chondroitin suphate in dietary supplements. Anionic analysis
of chondroitin sulphate, CS, was performed using a leading
electrolyte solution consisting of a mixture of 5mM HCl +
10mM glycylglycine+ 0.05% 2-hydroxyethylcellulose. The
terminating solution was 10mM citric acid. The separation
compartment contained a pre-separation Fluorinated
ethylene propylene (FEP) capillary coupled with an analytical
FEP capillary. The separation was carried out with the electro-
osmotic flow suppressed. The analytes were detected by
conductivity and UV (254nm) detectors.
Method Scope / Applicability:
Method is for Glucosamine and CS determination. All reviewer
comments are for CS only. The authors performed the
validation on tablets with stated daily doses of 600 and 1200
mg CS. Capsules, syrups and powders obtained from
manufacturers and domestic markets were analyzed,
however, were not part of the validation.
General Comments About the
Method:
• Raw data was not submitted for the reviewer.
• The validation was performed using analytical grade
chemicals and reagents. The standards were purchased from
Sigma and do not appear to be properly characterized.
Authors reported impurities being found in the reference
materials; CS-A being a mix of CS-A and CS-C.
• Accuracy was performed using standard addition of CS-A at
50% and 100%.
• Data on the effectiveness on sonication was not provided.
Stability of sample solution in a sonicator for 30 minutes was
not evaluated.