Determination of disodium cromoglycate in human urine by high-performance liquid chromatography with post-column photoirradiation-fluorescence detection

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 mu l. 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).