Background: A new approach for the simultaneous determination of ternary mixture, without prior separation steps, is proposed.
Method: This method is based on the difference change between the adjacent data points. The principal advantage of this method is using absorbance data, and not derivative data; hence the signal-to-noise ratio is not diminished. The method has been successfully applied to the simultaneous determination of ternary mixtures of the synthetic azo dyes, tartrazine (E102), sunset yellow (E110) and azorubine (E122). The mathematical explanation of the approach is elucidated. Beer’s law was obeyed in the concentration range 2-30 µgml-1 for E122, 120 µgml-1 E110 and 1-20 µgml-1 E102. Result: The results indicated a good concordance compared to standards, taken and recovered by MCR. The new method has the advantage of high sensitivity, extremely low detection limits, good selectivity, rapid analysis and using of inexpensive instruments.Keywords: Adjacent data points, spectrophotometry, mean centering ratio, azo dyes.