Influence of AEO-9 on Ultraviolet Absorbance Spectrum of TDBAC Reduced by beta-CD

The interaction between tetradecyl dimethyl benzyl ammonium chloride (TDBAC) and fatty alcohol polyoxyethylene ether (AEO-9) could significantly interfere with the ultraviolet absorption intensity of TDBAC in an aqueous solution. The results showed that AEO-9 can improve the ultraviolet absorption intensity of TDBAC and can greatly decrease the apparent critical micelle concentration (cmc) of TDBAC. When the concentration of AEO-9 increased from 0 to 0. 150 and 0. 300 mmol . L-1 the apparent cmc of TDBAC decreased from 1. 901 to 1. 739 mmol . L-1 and 1. 584 mmol . L-1, respectively. In TDBAC/AEO-9 aqueous solution, the ultraviolet absorption intensity of TDBAC was enhanced by adding 1 : 1 beta-cyclodextrin (beta-CD) according to the molar amount of TDBAC, with the addition of 0. 800 mmol . L-1 beta-CD, the ultraviolet absorption intensity of TDBAC increased from 0. 259 to 0. 270. When the concentrations of AEO-9 increased from 0 to 0. 150 or 0. 300 mmol . L-1 TDBAC micelles could not be formed in the range of 0. 600 similar to 2. 800 mmol . L-1 in aqueous solutionby adding 1 : 1 beta-CD. What is more, the interference of AEO-9 on UV Spectrum of TDBAC could be greatly reduced, and the recovery rate of TDBAC in TDBAC/AEO-9 aqueous solution changed from 86. 3% similar to 107. 5% to 101. 9% similar to 103. 9% , which showed that the detection accuracy of TDBAC was significantly improved. The results of Job's experiments showed that TDBAC/AEO-9 inclusion should be formed with the molar ratio of 1 : 1 in an aqueous solution. The results of FTIR andTG-DSC showed that TDBAC molecules were more likely to form inclusion complexes with beta-CD rather than micelles in aqueous solution, which exhibited that the interference of AEO-9 on quantitative determination of TDBAC could be significantly reduced because of the formation of TDBAC/beta-CD inclusion in TDBAC/AEO-9 aqueous solutions.