AOAC SPDS Mid Year 2016
Existing Methods
• HPTLC – Lobo et al ., A HPTLC densitometric method for the determination of aloeverose in Aloe vera gel. Fitoterapia 2010 , 81, 231–233.
HPTLC conditions: Plate: Si-gel Si60F 254 Developing: n-butanol: n-propanol: l i l ti id t g ac a ace c ac : wa er (30:10:10:10 v/v/v/v). Reagents: anisaldehyde sulphuric acid reagent; heating the plate at 105–110°C for 5min.
aloeverose
Fig. HPTLC chromatogram of A. vera gel (from the above paper).
Existing Methods • Colorimetric Assay by Red Dye – Congo Red – Eberendu et al ., Quantitative Colorimetric Analysis of Aloe
Polysaccharides as a Measure of Aloe Vera Quality in Commercial Products. J. AOAC International , 2005 , 88 , 684‐691.
NH 3
O O
N
S
O - Na +
N
N
O O
+ Aloe polysaccharides
N
S
O - Na +
H 2 N
Congo red dye
• Complex of Congo red with polysaccharides and assayed at 540nm
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