2.4. Method validation
For validation of the method, we analyzed the response linearity
of the glucosamine standard, and method precision (repeatability
and reproducibility) and accuracy. Five different weights of glucosamine
standard (30–90 mg) were dissolved in 1% acetic acid
solution. The standard solutions were processed and derivatized as
described for the derivatization of sample hydrolysates. The derivatized
standards were analyzed for linearity of detection. To test
method repeatability, five replicate samples were prepared and
analyzed following the procedure outlined in the previous sections.
For method reproducibility, a second set of replicate samples (n = 5)
were prepared and analyzed by a second analyst using a different
instrument. The results were then compared to the results of the
first analyst. Method accuracy was determined using a blank matrix
spiked with chitosan at 50, 100, or 150% of the formulation target
content (33% chitosan) and analyzed.