Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis Minnesota 55455, United States.
Emerson Automation Solutions, 6021 Innovation Blvd, Shakopee Minnesota 55379, United States.
Anal Chem. 2021 Dec 21;93(50):16899-16905. doi: 10.1021/acs.analchem.1c03985. Epub 2021 Dec 8.
With a view to improving the sensor lifetime, solid-contact ion-selective electrodes (ISEs) were prepared with a plasticizer-free and cross-linked poly(decyl methacrylate) matrix, to which only the ionic sites, only the ionophore, or both the ionic sites and ionophore were covalently attached. In earlier work with covalently attached ionophores or ionic sites, it was difficult to discount the presence of ionophores or ionic site impurities that were not covalently attached to the polymer backbone because the reagents used to introduce the ionophore or ionic sites had high hydrophobicities. In this work, we deliberately chose readily available hydrophilic reagents for the introduction of covalently attached H ionophores with tertiary amino groups and covalently attached sulfonate groups as ionic sites. This simplified the synthesis and made it possible to thoroughly remove ionophores and ionic sites not covalently attached to the polymer backbone. Our results confirm the expectation that hydrophobic ISE membranes with both covalently attached ionophores and ionic sites have impractically long response times. In contrast, ISEs with either covalently attached H ionophores or covalently attached ionic sites responded to pH with quick Nernstian responses and high selectivity. Both conventional plasticized poly(vinyl chloride) (PVC)-based ISEs and the new poly(decyl methacrylate) membranes were exposed to 90 °C heat for 2 h, 10% ethanol for 1 day, or undiluted blood serum for 5 days. In all three cases, the poly(decyl methacrylate) ISEs exhibited properties superior to conventional PVC-based ISEs, confirming the advantages of the covalent attachment.
为了提高传感器的寿命，制备了一种无增塑剂和交联的聚（癸基甲基丙烯酸酯）基质的固态接触离子选择性电极（ISE），其中仅共价连接了离子位点、仅离子载体或离子位点和离子载体。在以前的共价连接离子载体或离子位点的工作中，由于用于引入离子载体或离子位点的试剂具有高疏水性，因此很难排除未共价连接到聚合物主链上的离子载体或离子位点杂质的存在。在这项工作中，我们故意选择了易于获得的亲水性试剂，用于引入具有叔氨基的共价键合 H 离子载体和共价键合的磺酸盐基团作为离子位点。这简化了合成过程，并能够彻底去除未共价连接到聚合物主链上的离子载体和离子位点。我们的结果证实了预期，即具有共价键合离子载体和离子位点的疏水性 ISE 膜具有不切实际的长响应时间。相比之下，具有共价键合 H 离子载体或共价键合离子位点的 ISE 对 pH 的响应具有快速的能斯特响应和高选择性。传统的增塑聚氯乙烯（PVC）基 ISE 和新型聚（癸基甲基丙烯酸酯）膜都在 90°C 下加热 2 小时、10%乙醇中浸泡 1 天或未经稀释的血清中浸泡 5 天。在所有三种情况下，聚（癸基甲基丙烯酸酯）ISE 的性能均优于传统的 PVC 基 ISE，证实了共价键合的优势。
