A Novel Fluorescence Quenching Method for the Determination of Aloe Polysaccharide

Alizarin red (AR) can bind with aloe polysaccharide (APS) in doubly de‐ionized water to form a red complex resulting in fluorescence quenching of it. The maximum fluorescence quenching wavelength is 572 nm. The chromogenic reaction is rapid and the fluorescence intensity remains stable for at least 2 h at room temperature. The quenched fluorescence intensity (ΔF) is directly proportional to APS concentration. Based on this interaction, a sensitive and selective fluorophotometric method is proposed for the determination of APS. The optimal experiment conditions were established. The corresponding linear equation is (F=0.8807C+1.8132, R²=0.9999. The quantification and detection limits are 0.4752 and 0.1425 µg·mL^?1, respectively. The linear range is 0.444–16.65 µg·mL^?1 for APS and the mean recovery (100.2±2)%, RSD?3%. The effect of various substances on the determination of APS was also investigated in detail, and the results show that most of the studied coexistent substances can be tolerated in considerable amounts. The proposed method is sensitive, simple, fast and suitable for routine assay.