Spectrofluorimetric determination of quercetin in pharmaceutical dosage forms

Abstract

The simple, accurate and precise method based on fluorescence properties of aluminium (III)–quercetin complex, for the determination of quercetin has been developed and validated. The complex has strong emission at pH 3.30, lem = 480 nm, with lex = 420 nm. Linearity range of quercetin determination was 1.5 - 60.5 ng mL-1 with LOD 0.09 ng mL-1 and LOQ 0.27 ng mL-1. Recovery values in the range of 99.9 – 100.2 % indicate a good accuracy of the method. The established method was applied for the determination of quercetin in capsules, with Recovery value 98.3 %, standard deviation 0.22 % and coefficient of variation 0.09 %. The reliability of the method was checked by RP-HPLC/UV method for capsules with direct determination of quercetin after separation. The good agreement between two methods indicates the applicability usability of the proposed spectroflurometric method for quercetin determination in pharmaceutical dosage forms, with high reproducibility, and enables direct and simple determination without its prior extraction from samples. The proposed spectrofluorimetric method has much better sensitivity and about 1000 times lower LOD and LOQ values compared to data reported in literature.

Keywords

• quercetin
• flavonoids
• spectrofluorimetric determination
• rp-hplc
• capsules