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本研究发展了一种采用磁性介孔微球Fe3O4@nSiO2@mSiO2测定溶液中多环芳烃(PAHs)和牛血清蛋白(BSA)结合常数(KBSA)的方法.在合成Fe3O4@nSiO2@mSiO2微球时,将少量的十六烷基三甲基铵阳离子(CTAM+)模板保留在介孔内作为萃取水体中自由溶解态PAHs的吸附剂,而与溶液中的BSA及其结合的PAHs则由于体积排阻作用不被萃取.微球外层很薄的介孔层(≈50 nm)显著缩短了水体中PAHs向介孔内CTAM+迁移的路径,而微球较大的表面积(186m2/g)和孔体积(0.16 cm3/g)增大了微球在水体中与PAHs的接触面积,使其能够快速富集水体中的自由溶解态PAHs,萃取平衡时间(t90%)仅为66 min.实验测定了不同BSA浓度条件下PAHs自由溶解态分数,并据此计算得到PAHs与BSA的结合常数lgKBSA=3.94～5.00,与微耗损固相微萃取方法测得的结果基本一致,而平衡时间仅为后者的1/200,显著地提高了工作效率.
In this study, a method for the determination of polycyclic aromatic hydrocarbons (PAHs) and bovine serum albumin (BSA) binding constant (KBSA) using magnetic mesoporous microspheres Fe3O4 @ nSiO2 @ mSiO2 has been developed.In the synthesis of Fe3O4 @ nSiO2 @ mSiO2 microspheres , A small amount of cetyltrimethylammonium cation (CTAM +) template remains in the mesopores as adsorbents for the free-dissolved PAHs in the extracted water, while the BSA in solution and the PAHs bound to them are due to the size exclusion (≈50 nm) in the outer layer of microspheres significantly shortened the migration of PAHs to messenger CTAM + in water, whereas the larger surface area of the microspheres (186 m2 / g) and pore volume (0.16 cm3 / g) increases the contact area between PAHs and water in the microspheres, making it possible to rapidly enrich free-dissolved PAHs in water with an extraction equilibrium time (t90%) of only 66 min. BSA concentration free PAHs dissolved fraction, and calculated the PAHs and BSA binding constant lgKBSA = 3.94 ~ 5.00, and micro-depleted solid phase microextraction method measured results are consistent, and the balance of time is only the latter 1/200, significantly improve work efficiency.