Sulfonamide drugs: Low-cost spectrofluorometric determination using a computer monitor calibrator for detection

A possibility of the use of a common monitor calibrator as a portable and inexpensive tool for the fluorometric determination of sulfonamide drugs after their reaction with fluorescamine was examined. The luminescence measurements with a calibrator are based on irradiation of a test sample by the device lamp with a broadband spectrum in the visible and near UV regions and simultaneous registration of the secondary radiation by the device detector. Two types of cuvettes with black light absorbing sides eliminating the reflected self-radiation were tested. The commercially available Eppendorf-type black plastic microtubes ("LightSafe") were suggested as a good option for such measurements. It was shown that a monitor calibrator can be applied for optimization of the determination conditions. By the example of sulfanilamide and sulfamethazine, it was shown that the procedure should be carried out at pH 4-6 and fluorescamine concentration of 200 μmol L^-1, and 40 min of the interaction. The limit of detection of sulfanilamide and sulfamethazine using a monitor calibrator is 0.9 μmol L^-1 and 0.8 μmol L^-1, respectively, which is comparable with their spectrophotometric determination.