Simultaneous determination of carvedilol and ampicillin sodium by synchronous fluorimetry

The carvedilol and ampicillin sodium were simultaneously determined by the synchronous fluorimetry. With excitation wavelength at 254 nm, the maximum emission wavelengths of carvedilol and ampicillin sodium were at 357 and 426 nm, respectively. Because the emission spectra of carvedilol and ampicillin sodium were overlapped partially, carvedilol and ampicillin sodium cannot be determined directly by normal fluorimetric method. However, the synchronous fluorimetry can be used for determining both drugs simultaneously without separation procedure. The Δλ = 80 nm was used. Iso-propanol was selected as sensing reagent. Effects of pH, organic solvents and foreign ions on the determination of both drugs were studied. The linear relationship was obtained between the relative fluorescence intensity and concentration of carvedilol and ampicillin sodium in the range of 0.005-0.1 and 5.0-70.0 μg ml−1, respectively. The linear regression equation of calibration graph for carvedilol is C = 0.000151F - 0.00210, and for ampicillin sodium is C = 0.0770F - 2.62. The correlation coefficient of linear regression equation is 0.9995 for carvedilol and 0.9998 for ampicillin sodium, respectively. The detection limit is 1 ng ml−1 for carvedilol and 1 μg ml−1 for ampicillin sodium. The relative standard deviations of carvidelol and ampicillin sodium are 2.47 and 1.61%, respectively. The recovery is from 96.0 to 103.0% for carcvedilol and from 98.0 to 105.0% for ampicillin sodium. This method was rapid, simple and highly sensitive for the determination of carvedilol and ampicillin sodium without pre-separation. The results obtained by this method agreed with those by the official methods. This method can be used for the determination of carvedilol and ampicillin sodium in the medicine dosage.