formation of ternary complexes containing surfactant monomers,
which led to the micelles formation of high molar absorptivity and,
therefore, high sensitivity (Shokrollahi et al., 2008; Rodrigues et al.,
2005). It was found that the absorption spectrum of Al-ECR in the
presence ofDTAB gave highest sensitivity and red shift to maximum
wavelength of 584 nm (Fig. 3). Therefore, DTAB was chosen as a
suitable surfactant for enhancing the sensitivity of Al-ECR.
3.1.2. Effect of pH
The pH of the reaction medium was investigated at 584 nm by
measuring the absorbance of Al-ECR complex in the presence of
DTAB in the pH range of3.5–6.5 using 1 mol L1 ofacetate buffer. A
sequential injection system was used for aspiration of a premixed
solution of Al-ECR complex in the presence of DTAB using the
volume of 200 mL. The results were compared with the results