Determination of Disodium Cromoglycate in Human Urine by High-performance Liquid Chromatography With Post-column Photoirradiation–Fluorescence Detection

Abstract

For the determination of disodium cromoglycate in urine, a fluorimetric method using HPLC post-column photoirradiation has been developed. The mobile phase consisted of a 35 mmol l ^{- 1} phosphate buffer (pH 8)–methanol (7 + 3, %v/v) containing 75 mmol l ^{- 1} hydrogen peroxide and 20 mmol l ^{- 1} 18-crown-6. The 18-crown-6 was used for separation adjustment of the disodium cromoglycate in the urine sample. Photoirradiation was carried out in tubing wound around a germicidal light in a reactor equipped with an air- cooling fan. The fluorescence was monitored with excitation at 325 nm and emission at 448 nm. The calibration graph for disodium cromoglycate was linear over the range 38–2340 ng ml ^{- 1} using an injection volume of 100 µl. The pretreatment of the urine samples consisted of diluting and filtering steps. The mean recovery of disodium cromoglycate from urine was 99.1 ± 2.4% (n = 6).