Constant-wavelength Synchronous Fluorescence Spectrometric to Simultaneous Determination of Trimethoprim and Norfloxacin by Multivariate Calibration

The constant-wavelength synchronous excitation and emission spectra(△λ=150 nm) of trimethoprim and norfloxacin were measured.It was found that the spectra were seriously overlapped,and it is difficult to determine these two compounds simultaneously.In this paper,the chemometrics,such as partial least squares(PLS) and principal components regression(PCR) were applied to resolve the overlapped spectra and determine these two compounds in pharmaceutical sample.Satisfied quantitative results were attained.The linear ranges were 0.04~0.32mg/L and 0.01~0.08mg/L for Trimethoprim and Nnorfloxacin,respectively.The limits of detection were 10.4 μg/L and 1.1 μg/L for them,respectively.