Paper-based ion-selective optodes (ISOs) allow for low-cost ion measurements using widely accessible optical detectors such as smartphones, representing an attractive analytical platform for medical testing and environmental monitoring. Previously reported paper-based ISOs rely on plasticized PVC membranes or PVC/plasticizer-free adsorption layers containing hydrophobic sensing chemicals. In this paper, we studied a new format of paper-based ISOs, in which a plasticizer phase containing sensing chemicals is deposited onto cellulose paper without using a hydrophobic polymer like PVC. Compared to ISOs without plasticizers and polymers, the plasticizer-based ISOs show much higher pH sensitivity when using chromoionophore I and tetrakis[3,5-bis(trifluoromethyl)phenyl]borate as the sensing chemicals. When the sensing layer further contains a solid ionophore with high molecular rigidity, the plasticizer-based ISOs for cations also exhibit enhanced sensitivity than the plasticizer-free ISOs. However, when the ionophore is a liquid at room temperature or has a long alkyl chain, the plasticizer-based and plasticizer-free ISOs have comparable responses because the ionophore behaves as a pseudo-plasticizer. Compared to ISOs with both plasticizers and polymers, the elimination of hydrophobic polymers like PVC makes inkjet printing more efficient and preserves the capillary action of the porous paper. By using the newly launched Samba cartridge with smaller nozzles, the plasticizer-based and polymer-free optodes for sodium, potassium, and calcium ions are prepared by inkjet printing for the first time. In an example application, the inkjet-printed plasticizer-based and polymer-free ISOs are used for colorimetric measurements of urine calcium.

中文翻译：

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纤维素纸上基于增塑剂且不含聚合物的离子选择性光极


纸基离子选择性光极 (ISO) 允许使用智能手机等广泛使用的光学探测器进行低成本离子测量，为医疗测试和环境监测提供了一个有吸引力的分析平台。先前报道的纸基 ISO 依赖于增塑 PVC 膜或含有疏水传感化学物质的 PVC/不含增塑剂的吸附层。在本文中，我们研究了一种新形式的纸基ISO，其中含有传感化学物质的增塑剂相沉积在纤维素纸上，而不使用PVC等疏水性聚合物。与不含增塑剂和聚合物的 ISO 相比，当使用发色离子载体 I 和四[3,5-双(三氟甲基)苯基]硼酸盐作为传感化学品时，基于增塑剂的 ISO 表现出更高的 pH 敏感性。当传感层还包含具有高分子刚性的固体离子载体时，基于增塑剂的阳离子ISO也表现出比不含增塑剂的ISO更高的灵敏度。然而，当离子载体在室温下为液体或具有长烷基链时，基于增塑剂的 ISO 和不含增塑剂的 ISO 具有相似的响应，因为离子载体表现为假增塑剂。与同时含有增塑剂和聚合物的 ISO 相比，消除 PVC 等疏水性聚合物使喷墨打印更加高效，并保留了多孔纸的毛细管作用。通过使用新推出的具有较小喷嘴的Samba墨盒，首次通过喷墨印刷制备了基于增塑剂且不含聚合物的钠、钾和钙离子光极。在一个示例应用中，喷墨印刷的基于增塑剂且不含聚合物的 ISO 用于尿钙的比色测量。