DETERMINATION OF TERNARY MIXTURES OF VITAMINS BY RATIO-SPECTRA ZERO-CROSSING DERIVATIVE SPECTROPHOTOMETRY

The ratio-spectra zero-crossing first and third derivative spectrophotometry have been used for determining ternary mixtures of Vitamin B6, Vitamin B1 and Vitamin B12. The procedures are accurate, nondestructive and do not require solving of equations. In both methods, calibration graphs are linear, with zero-intercept, up to 48 mu g/ml of Vitamin B6, 64 mu g/ml of Vitamin B1 and 60 mu g/ml of Vitamin B12. Correlation coefficients range from 0.9999 to 1.0000. Working wavelengths, 311, 272.5 and 215.5 nm, respectively,in the 1st-derivative mode and 300.5, 271.5 and 365 nm in the 3rd-derivative mode. Detection limits For each drug at p=0.01 level of significance were calculated to be 0.002, 0.009 and 0.004 mu g/ml and 0.002, 0.004 and 0.001 mu g/ml, in the first and third-derivative methods, respectively. Both methods apply favourably to either synthetic mixtures or commercial injections for these drugs. An exhaustive statistical treatment of the experimental findings was performed to confirm the validity of the methods.