UV-VIS studies on interaction between sodium dioctylsulfosuccinate (AOT) and methyl red

Abstract

"This paper deals with the interaction of sodium dioctylsulfosuccinate (AOT) and methyl red (MR) by UV-Vis spectrophotometry at 298.15 K. The concentration of AOT varies from 0 to 0.12530 mol/kg and the concentration of methyl red is 3.71×10-5 M. Here, water concentration is defined by the R parameter. The R parameter in this study varied from 0 to 20. Two intense absorption bands were observed within the 380 to 540 nm wavelength of methyl red in methanol. Band 1(380 to 450 nm) of methyl red contains a higher absorbance peak than band 2(450 to 540 nm). When the concentration of AOT increased, band 1(380 - 450 nm) of methyl red decreased the absorbance peak, whereas band 2 (450 to 540 nm) of methyl red increased the absorbance peak with increasing AOT concentration. Band 1 shows a hypochromic shift of methyl red with an increase in AOT concentration, whereas band 2 shows a hyperchromic shift of methyl red with an increase in AOT concentration. On comparing the absorbance versus concentration graph for different R parameters, we observed that absorbance increases with the increase in the R parameter. The binding constant and distribution constant were calculated using a non-linear regression procedure (NLREG). The experiment shows the effect of methanol, AOT and water concentration on methyl red."