In this work a new modified standard addition method for simultaneous spectrophotometric determination of Sunset yellow (SY) and Quinoline yellow (QY) is used. The generalized Net Analyte Signal Standard Addition Method (GNASSAM) was introduced for simultaneous standard addition of analytes. By applying this method the concentrations of analytes are determined in a single step. The applicability of new method was used for the simultaneous determination of strongly overlapped spectra of SY and QY in a real sample without using any separation step. GNASSAM was also used to calculate figures of merit. Moreover, good limits of detection (SY = 0.13 and QY = 0.16 mgL -1 ) and suitable selectivity and sensitivity were determined. HPLC method was applied for finding subspace in binary mixtures of real samples. The results of investigated method for real sample were compared with HPLC results. The obtained results were in a good agreement with those of HPLC method.

Recently a novel method for determination of an analyte in the presence of known interferences called the net analyte signal standard addition method (NASSAM) was introduced. Although NASSAM was used for individual standard addition, a novel generalized net analyte signal standard addition method (GNASSAM) was used for simultaneous standard addition. By applying the proposed method, simultaneous determination of components was done in a single step. Also, this method can be applied for linearly dependent concentrations. Sunset yellow and Carmoisine demonstrate strong spectra overlap with typical application of a spectrophotometry technique. GNASSAM was used for simultaneous determination of Sunset yellow and Carmoisine in synthetic binary mixtures and real samples. The investigated method was also used to calculate figures of merit; moreover, good limits of detection (SY ¼ 0.15 and CA ¼ 0.18 mg L À1 ) and suitable selectivity and sensitivity were determined. A HPLC method was applied for finding the subspace in binary mixtures of real samples. The obtained results for real samples were compared with the HPLC results. The obtained results were in good agreement with those of the HPLC method.