Abstract: The interaction between sodium dodecyl benzene sulfonate (SDBS) and ethoxylated octylphenol (OP-10) could have a significant impact on the quantitative determination of SDBS/OP-10 binary blend in aqueous solution.Experimental results indicated that the apparent critical micelle concentration (cmc) values and the fluorescence intensities of SDBS measured by synchronous fluorescence spectrometry could be greatly changed because of the existence of OP-10.The cmc values of SDBS reduce from 1.183 mmol/L to 1.011,0.861 and 0.658 mmol/L when the concentrations of OP-10 increase from 0 to 0.500,1.000 and 2.000 mmol/L in water respectively,and the fluorescence intensities of SDBS would be increased with the increasing concentration of OP-10.On the other hand,the existence of SDBS could also have a significant impact on the quantitative analysis of OP-10 in aqueous solution by chemical colorimetry.The results indicated that the interaction between SDBS and OP-10 could be greatly reduced by adding 1∶1 hydroxypropyl-β-cyclodextrin (HP-β-CD) according to the molar amount of SDBS,thus,the recovery rates of SDBS and OP-10 change from 80.2%-105.2% and 65.4%-93.1% to 101.1%-101.4% and 101.4%-102.6% respectively,which showed that the measurement veracity of SDBS and OP-10 in SDBS/OP-10 binary blend has been greatly improved.The experimental results of Job’s test and FT-IR analysis exhibited that the interaction between SDBS and OP-10 could be greatly reduced because of the formation of HP-β-CD/SDBS inclusion compound with molar ratio of 1∶1.

Key words: sodium dodecyl benzene sulfonate, ethoxylated octylphenol, blend system, hydroxypropyl-β-cyclodextrin, revised spectrum, quantitative analysis