Institute of Analytical Chemistry, Department of Chemistry, Zhejiang University , Hangzhou 310058, P. R. China.
Key Laboratory for Advanced Materials & Institute of Fine Chemicals, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, PR China.
Anal Chem. 2016 Aug 2;88(15):7821-7. doi: 10.1021/acs.analchem.6b01866. Epub 2016 Jul 22.
We report in this work the fabrication of ultrathin silica nanochannel membranes inhomogeneously modified by polydimethysiloxane (PDMS), designated as PDMS-SNM, for hydrophobicity-based molecular filtration and detection. The modification was accomplished by spatially selective evaporation of hydrophobic PDMS oligomers onto the top surface of the membrane and orifice of silica nanochannels. Thanks to this hydrophobic ultrathin layer and beneath ultrasmall channels (2-3 nm in diameter), only small hydrophobic molecules are able to transport through the PDMS-SNM, whereas hydrophilic and large ones are remarkably inhibited. We first employed this PDMS-SNM as the molecular sieving matrix for selective electrochemical detection of hydrophobic organophosphates (OPs) in milk samples without pretreatment. The PDMS-SNM modified electrode displayed an excellent analytical performance and antifouling/anti-interference ability. We also prepared the free-standing PDMS-SNM consisting of perforated channels, which could filtrate molecules based on their hydrophobicity with an excellent selectivity. As demonstrated, 2,4,6-trinitrotoluene and dopamine could be separated with a selectivity coefficient as high as 335. Moreover, because of the inhomogeneous nanochannel structure and ultrasmall thickness, a remarkably high flux of hydrophobic molecules across the PDMS-SNM was obtained, which was 3-4 orders of magnitude higher than that reported previously.
我们在这项工作中报告了通过聚二甲基硅氧烷（PDMS）不均匀修饰的超薄二氧化硅纳米通道膜的制造，称为 PDMS-SNM，用于基于疏水性的分子过滤和检测。通过将疏水性 PDMS 低聚物选择性地蒸发到膜的顶部表面和二氧化硅纳米通道的孔口上，实现了这种修饰。由于这种疏水性超薄层和下面的超小孔径（直径为 2-3nm），只有小的疏水分子才能通过 PDMS-SNM 传输，而亲水的和大的分子则受到显著抑制。我们首先将这种 PDMS-SNM 用作分子筛分基质，用于未经预处理的牛奶样品中疏水有机磷（OP）的选择性电化学检测。PDMS-SNM 修饰电极表现出出色的分析性能和抗污/抗干扰能力。我们还制备了由穿孔通道组成的独立 PDMS-SNM，其可以根据分子的疏水性进行过滤，具有出色的选择性。结果表明，2,4,6-三硝基甲苯和多巴胺可以用高达 335 的选择性系数进行分离。此外，由于不均匀的纳米通道结构和超薄厚度，获得了疏水分子穿过 PDMS-SNM 的高流量，比以前报道的高 3-4 个数量级。
