Abstract:

The interactions between polyethylene glycol tert-octylphenyl ether （Triton X-100） and dodecyl trimethyl ammonium bromide （DTAB） has significant effects on the ultraviolet spectral signals of Triton X-100 in the aqueous mixture. The results show that DTAB can increase the absorbance of Triton X-100 in aqueous solution and also has a remarkable influence on the apparent critical micelle concentration （cmc） of Triton X-100, where the apparent cmc values of Triton X-100 are reduced from 0.187 g/L to 0.170 and 0.154 g/L when the concentration of DTAB increase from 0 to 0.100 and 0.200 mmol/L, respectively. Adding β-cyclodextrin （β-CD） by molar ratio of 1∶1 between Triton X-100 and β-CD in the aqueous mixture of Triton X-100 and DTAB can not only effectively reduce the interactions between Triton X-100 and DTAB, but also enhance the ultraviolet signal intensity of Triton X-100. Thus, the recovery rates of Triton X-100 change from 92.0%-97.3% to 98.8%-102.2%, which indicate that the measurement accuracy of Triton X-100 has been greatly improved. The results of Job’s experiment and infrared spectrum show that, β-CD can eliminate the interference （arising from other coexisting components） to the UV spectra of Triton X-100, which is primarily attributed to the formation of inclusion complexes with Triton X-100 molecules entering into the cavities of β-CD molecules.

Key words: polyethylene glycol tert-octylphenyl ether, β-cyclodextrin;, micelle, UV spectra