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Existing Methods
•
Colorimetric Assay by Red Dye – Alizarin Red
–
Gu
et al
., Binding interaction between aloe polysaccharide and
alizarin red by spectrophotometry and its analytical application.
Carbohydrate Polymers.
2010
,
80
, 115–122.
O OH
OH
SO
3
-
Na
+
Aloe polysaccharides
+
•
Complex of alizarin red with polysaccharides and assayed
at 325nm and 516nm
O
alizarin red
Existing Methods
•
Colorimetric Assay of Acetyl Groups of Polysaccharides
–
Aloe Products for Food Raw Material, Chinese National Standard,
QB/T 2489 2007
Th t l
l
h id
t d ith
O
R
O
NH
2
OH
N
OH
O
H
N
O
O Fe
/3
H
1/3Fe
3+
Acetohydroxamic Acid
Ferric
-
Acethydroxamic Acid Complex
•
e ace y groups on po ysacc ar es are reac e w
hydroxylamine to form acetohydroxamic acid. The
resulted acetohydroxamic acid is reacted with ferric
trichloride to form a ferric‐acethydroxamic acid complex
and measured 540nm.