Suzuki H, Arakawa H, Sasaki S, Karube I
Institute of Materials Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba Science City, 305-8573, Japan.
Anal Chem. 1999 May 1;71(9):1737-43. doi: 10.1021/ac9811468.
The Severinghaus-type pCO(2) electrode was miniaturized and batch-fabricated using semiconductor and micromachining techniques. Anodically grown iridium oxide film (AIROF) was employed as the pH sensing element to detect a local pH change caused by the infusion of CO(2). The AIROF showed a super-Nernstian response with a slope of approximately -80 mV/pH at 25 °C. A novel thin-film Ag/AgCl structure was also used. It features a hydrophobic membrane which covers the entire silver layer and the AgCl layer grown from the periphery of the silver pattern. The open-circuit potential of the Ag/AgCl element drifted to the negative side at -0.1 to -0.2 mV h(-1). A microcavity in which the electrolyte solution was filled was anisotropically etched in a silicon substrate, and a silicone rubber gas-permeable membrane was formed on the sensitive area. The miniature pCO(2) electrode showed a distinct response to the variation in concentration of dissolved CO(2). The inherent characteristics of the Severinghaus electrode were confirmed in terms of its response and calibration curve. The selectivity of the electrode was satisfactory in view of its application to clinical analysis.
采用半导体和微加工技术将Severinghaus型pCO₂电极进行了小型化和批量制造。阳极生长氧化铱膜（AIROF）用作pH传感元件，以检测因注入CO₂而引起的局部pH变化。AIROF在25℃时呈现超能斯特响应，斜率约为-80 mV/pH。还采用了一种新型的薄膜Ag/AgCl结构。其特点是有一层疏水膜覆盖整个银层以及从银图案周边生长的AgCl层。Ag/AgCl元件的开路电位以-0.1至-0.2 mV h⁻¹的速率向负向漂移。在硅基板中各向异性蚀刻出一个填充有电解质溶液的微腔，并在敏感区域形成了硅橡胶透气膜。微型pCO₂电极对溶解CO₂浓度的变化表现出明显的响应。从其响应和校准曲线方面证实了Severinghaus电极的固有特性。鉴于其在临床分析中的应用，该电极的选择性令人满意。
