Particle Technology Laboratory, Department of Mechanical and Process Engineering, Institute of Process Engineering, ETH Zurich, CH-8092 Zurich, Switzerland.
Anal Chem. 2010 May 1;82(9):3581-7. doi: 10.1021/ac902695n.
Acetone in the human breath is an important marker for noninvasive diagnosis of diabetes. Here, novel chemo-resistive detectors have been developed that allow rapid measurement of ultralow acetone concentrations (down to 20 ppb) with high signal-to-noise ratio in ideal (dry air) and realistic (up to 90% RH) conditions. The detector films consist of (highly sensitive) pure and Si-doped WO(3) nanoparticles (10-13 nm in diameter) made in the gas phase and directly deposited onto interdigitated electrodes. Their sensing properties (selectivity, limit of detection, response, and recovery times) have been investigated as a function of operating temperature (325-500 degrees C), relative humidity (RH), and interfering analyte (ethanol or water vapor) concentration. It was found that Si-doping increases and stabilizes the acetone-selective epsilon-WO(3) phase while increasing its thermal stability and, thus, results in superior sensing performance with an optimum at about 10 mol % Si content. Furthermore, increasing the operation temperature decreased the detector response to water vapor, and above 400 degrees C, it was (<or=0.7) always below the threshold (10.6) for fake diabetes detection in ideal conditions. At this temperature and at 90% RH, healthy humans (<or=900 ppb acetone) and diabetes patients (>or=1800 ppb) can be clearly distinguished by a remarkable gap (40%) in sensor response. As a result, these solid state detectors may offer a portable and cost-effective alternative to more bulky systems for noninvasive diabetes detection by human breath analysis.
人呼气中的丙酮是一种用于非侵入性诊断糖尿病的重要标志物。在此，开发了新型的抗化学试剂电阻式探测器，它可以在理想（干燥空气）和实际（高达 90%相对湿度）条件下快速测量超低浓度的丙酮（低至 20ppb），并具有高信噪比。探测器薄膜由（高灵敏度）纯和 Si 掺杂的 WO(3)纳米颗粒（直径为 10-13nm）组成，这些纳米颗粒在气相中生成，并直接沉积在叉指电极上。研究了它们的传感性能（选择性、检测限、响应和恢复时间）作为操作温度（325-500°C）、相对湿度（RH）和干扰分析物（乙醇或水蒸气）浓度的函数。结果表明，Si 掺杂增加并稳定了对丙酮具有选择性的 ε-WO(3)相，同时提高了其热稳定性，从而导致在约 10mol% Si 含量下具有更好的传感性能。此外，升高操作温度会降低对水蒸气的探测器响应，而在 400°C 以上，它总是低于理想条件下用于虚假糖尿病检测的阈值（10.6）。在这个温度和 90% RH 下，健康人（丙酮含量<900ppb）和糖尿病患者（丙酮含量>1800ppb）可以通过传感器响应的明显差异（40%）来清晰区分。因此，这些固态探测器可能为通过人体呼吸分析进行非侵入性糖尿病检测提供了一种便携式且具有成本效益的替代方案，而不是更庞大的系统。
