Mizuta Tatsumi, Takai Shu, Nishihata Toshiki, Sueyoshi Kenji, Endo Tatsuro, Hisamoto Hideaki
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuencho, Nakaku, Sakai, Osaka 599-8531, Japan.
Analyst. 2020 Aug 21;145(16):5430-5437. doi: 10.1039/d0an00335b. Epub 2020 Jul 14.
Herein, a fully lipophilic ionic liquid (IL) comprising a lipophilic fluorescein anion and a trihexyltetradecylphosphonium cation was synthesized and used as the plasticizer for a plasticized poly(vinyl chloride) (PVC) membrane optode. Systematic investigation of the alkyl chain length of the fluorescein anion proved the significance of lipophilicity for obtaining the reversible absorbance measurements. A PVC membrane fabricated with the synthesized lipophilic IL was observed to comprise an unusually high dye concentration (915 mmol kg) and exhibited good sensitivity as well as response time in its sensor performance. The sensitivity of the presented PVC membrane was 26-fold higher than that of a conventional optode membrane with the same membrane thickness and the same lipophilic dye of typical dye content (1 wt%). The response time was observed to be >120-fold faster by using a significantly thinner PVC membrane (approx. 140 nm). Heparin is known to be a polyanionic anticoagulant, and the presented PVC membrane exhibited an extremely fast response (20-150 seconds) to the heparin in diluted serum within the required concentration region. Thus, the lipophilic IL-based dye could significantly improve the sensor performance in conventional optodes, especially for an analyte showing slow diffusion, such as macromolecular heparin.
在此，合成了一种包含亲脂性荧光素阴离子和三己基十四烷基鏻阳离子的全亲脂性离子液体（IL），并将其用作增塑聚氯乙烯（PVC）膜光极的增塑剂。对荧光素阴离子烷基链长度的系统研究证明了亲脂性对于获得可逆吸光度测量的重要性。观察到用合成的亲脂性离子液体制造的PVC膜包含异常高的染料浓度（915 mmol/kg），并且在其传感器性能方面表现出良好的灵敏度以及响应时间。所呈现的PVC膜的灵敏度比具有相同膜厚度和相同典型染料含量（1 wt%）的亲脂性染料的传统光极膜高26倍。通过使用明显更薄的PVC膜（约140 nm），观察到响应时间快>120倍。肝素是一种已知的聚阴离子抗凝剂，所呈现的PVC膜在所需浓度范围内对稀释血清中的肝素表现出极快的响应（20 - 150秒）。因此，基于亲脂性离子液体的染料可以显著改善传统光极中的传感器性能，特别是对于显示缓慢扩散的分析物，如大分子肝素。
