基于β-环糊精的高矿化度水中曲拉通X-405的检测新方法

A new method for quantitative determination of Triton X-405 in high-mineralization water based on β-cyclodextrin

油田压裂用水矿化度高,为了降低压裂用水对紫外光谱法检测聚乙二醇叔辛基苯基醚(曲拉通X-405)产生的影响,采用添加适量β-环糊精(β-CD)作为屏蔽剂来消除压裂用水的干扰作用。研究结果表明,压裂用水能明显降低曲拉通X-405的吸光度和临界胶束浓度(cmc),在压裂用水中,100.0 mg/L曲拉通X-405在最大吸收波长224 nm处的吸光度降幅达6.67%,曲拉通X-405的cmc也由蒸馏水中的103.978 mg/L降低至97.056 mg/L。加入与曲拉通X-405相同物质的量的β-环糊精后,压裂用水对曲拉通X-405吸光度的干扰作用显著降低,100.0 mg/L曲拉通X-405在224 nm处的吸光度降幅仅为1.99%,在20.0~160.0 mg/L范围内,曲拉通X-405在蒸馏水中及在压裂用水中均没有形成胶束,曲拉通X-405的检测回收率也由88.3%~97.4%改善至97.5%~99.6%。等摩尔连续变化法、FT IR及^(1)H NMR结果表明,在水溶液中曲拉通X-405与β-CD按物质的量比1∶1形成包结物,曲拉通X-405分子可以分别从β-CD分子空腔的宽、窄口径两端进入β-CD内腔,包结物的屏蔽作用是降低压裂用水对曲拉通X-405的干扰作用的根本原因。该方法为准确检测高矿化度压裂用水中的曲拉通X-405提供了新参考。

High-salinity oilfield fracturing water has interference on the quantitative analysis of polyethylene glycol tertoctylphenyl ether(Triton X-405)by ultraviolet spectroscopy.In this work,an appropriate amount of β-cyclodextrin(β-CD)was added as a“shielding”agent to reduce the interference of fracturing water.The results showed that the fracturing water could significantly reduce the absorbance and critical micelle concentration(cmc)of Triton X-405.In fracturing water,the absorbance of 100.0 mg/L Triton X-405 was decreased by 6.67% at the maximum absorption wavelength of 224 nm,and the cmc of Triton X-405 was also reduced from 103.978 mg/L to 97.056 mg/L.The impact of fracturing water on the absorbance of Triton X-405 could be significantly reduced by adding equimolar β-CD,and the decrease in absorbance of 100.0 mg/L Triton X-405 at 224 nm was only 1.99%.Triton X-405 could not form micelles in the mass concentration range of 20.0-160.0 mg/L by addingβ-CD in water or in fracturing water.As a result,the recovery of Triton X-405 in fracturing water was improved from 88.3%-97.4% to 97.5%-99.6%.The results of FT IR,^(1)H NMR and the method of continuous variations indicated that Triton X-405 and β-CD could form 1∶1 inclusion complex,and the Triton X-405 molecule could enter into the CD cavity both from the narrow rim and the wide rim.The shielding effect due to the formation of inclusion complex suppressed the interference of fracturing water on the determination of Triton X-405.The work could provide a new guidance for accurately determining Triton X-405 in high-salinity fracturing water.