Selective sensing of isoprene by Ti-doped ZnO for breath diagnostics
Selective sensing of isoprene by Ti-doped ZnO for breath diagnostics
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DOI：
10.1039/c6tb01335j
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发表时间：
2016-01-01
影响因子：
7
通讯作者：
Pratsinis, S. E.
中科院分区：
文献类型：
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作者：
Guntner, A. T.;Pineau, N. J.;Pratsinis, S. E.
呼出的异戊二烯可以实现降胆固醇治疗的非侵入性监测。在这里，我们报告异戊二烯选择性传感器在高相对湿度（RH）的第一次（据我们所知）。它是由纳米结构的，化学电阻钛掺杂氧化锌颗粒（10-20纳米晶体尺寸）生产的火焰喷雾热解（FSP），并直接沉积在一个步骤紧凑的传感器基板形成高度多孔膜。组分颗粒由稳定的Ti掺杂ZnO固溶体组成，Ti水平高达10摩尔%，显然是通过将Ti4+取代掺入ZnO纤锌矿晶格中并在颗粒表面占主导地位。这些Ti 4+点缺陷强烈增强异戊二烯敏感性（比纯ZnO高>15倍），并使ZnO具有异戊二烯选择性，同时还提高了其热稳定性。原位红外光谱证实，Ti 4+增强了Ti掺杂的ZnO与异戊二烯的表面相互作用，通过提供额外的网站的化学吸附的羟基物种。事实上，在2.5摩尔%的最佳Ti含量下，该传感器在90%RH下与丙酮、NH3和乙醇相比显示出上级异戊二烯响应。最值得注意的是，呼吸相关的异戊二烯浓度可以准确地检测到低至5 ppb，具有高（>10）信噪比。因此，已经开发出一种廉价的异戊二烯检测器，其可以容易地并入便携式呼吸分析仪中，用于代谢紊乱（例如胆固醇）的非侵入性监测。
Exhaled isoprene could enable non-invasive monitoring of cholesterol-lowering therapies. Here, we report an isoprene-selective sensor at high relative humidity (RH) for the first time (to our knowledge). It is made of nanostructured, chemo-resistive Ti-doped ZnO particles (10-20 nm crystal size) produced by flame spray pyrolysis (FSP) and directly deposited in one step onto compact sensor substrates forming highly porous films. The constituent particles consist of stable Ti-doped ZnO solid solutions for Ti levels up to 10 mol% apparently by substitutional incorporation of Ti4+ into the ZnO wurtzite lattice and dominant presence at the particle surface. These Ti4+ point defects strongly enhance the isoprene sensitivity (>15 times higher than pure ZnO) and turn ZnO isoprene-selective, while also improving its thermal stability. In situ infrared spectroscopy confirms that Ti4+ intensifies the surface interaction of Ti-doped ZnO with isoprene by providing additional sites for chemisorbed hydroxyl species. In fact, at an optimal Ti content of 2.5 mol%, this sensor shows superior isoprene responses compared to acetone, NH3 and ethanol at 90% RH. Most notably, breath-relevant isoprene concentrations can be detected accurately down to 5 ppb with high (>10) signal-to-noise ratio. As a result, an inexpensive isoprene detector has been developed that could be easily incorporated into a portable breath analyzer for noninvasive monitoring of metabolic disorders (e.g. cholesterol).