The appeared emission band within the range of 320e400 nm and the corresponding increase in its intensity after spike confirmed the presence of carvedilol in real sample, and hence validity of the procedure.
According to the calibration curve, results of triplicate analyses of spiked real sample showed the recovery of 94% with 6% relative standard deviation; consequently the concentration of free carvedilol in real sample was determined to be 15 ± 5 ngmL1