NADH-Fluorometric Biochemical Gas Sensor (Bio-Sniffer) for Evaluation of Indoor Air Quality
NADH-Fluorometric Biochemical Gas Sensor (Bio-Sniffer) for Evaluation of Indoor Air Quality
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DOI：
10.1109/jsen.2013.2257739
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发表时间：
2013-04
影响因子：
4.3
通讯作者：
H. Kudo;T. Yamashita;K. Miyajima;T. Arakawa;K. Mitsubayashi
中科院分区：
文献类型：
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作者：
H. Kudo;T. Yamashita;K. Miyajima;T. Arakawa;K. Mitsubayashi
研制了一种用于室内甲醛检测的光纤生化气体传感器（生物嗅探器），并对TiO 2降解甲醛的过程进行了监测。生物嗅探器将FA蒸气测量为还原的烟酰胺腺嘌呤二核苷酸（NADH）的荧光，其是FA脱氢酶（NADH）的酶促反应的产物。通常，酶在气相中失去其比活性。这使得生化气体监测变得困难。我们采用了一种带有固定化膜的微流动池，以防止在光极处的脱氢酶失活。采用峰值发射为335 nm的紫外发光二极管（UV-LED）作为激发光源。UV-LED的发射通过光纤被引入到光电管，并且在光电管处同轴地拾取NADH的荧光。为了提高灵敏度，引入了多LED光源，而不是以前报道的系统。光电倍增管被用作光电探测器。采用生化方法成功地进行了FA的连续监测，在亚ppb水平上具有高选择性。由于改进了激发源，使检测限提高到750 ppt。还使用光催化二氧化钛进行了实际样品测试。将标准气体流入光催化剂玻璃所在的池中，并使用生物嗅探器测量FA水平。因此，通过二氧化钛的催化反应的FA的降解被监测为真实的时间的FA的还原。研究结果表明，该方法可用于快速、方便地监测室内空气中游离甲醛。
A fiber-optic biochemical gas sensor (bio-sniffer) for assessment of indoor formaldehyde (FA) is fabricated and tested in monitoring of FA degradation by TiO2. The biosniffer measures FA vapor as fluorescence of reduced nicotinamide adenine dinucleotide (NADH), which is the product of enzymatic reaction of FA dehydrogenase (FALDH). Usually, an enzyme loses its specific activity in the gas phase. This makes biochemical gas monitoring difficult. We employ a microflow-cell with a FALDHimmobilized membrane to prevent the FALDH from deactivation at the optode. An ultraviolet light-emitting diode (UV-LED) with peak emission of 335 nm is employed as an excitation light source. Emission of the UV-LED is introduced to the optode through an optical fiber and fluorescence of NADH is picked up coaxially at the optode. To improve the sensitivity, a multi-LED light source is introduced instead of the previously reported system. A photomultiplier tube is utilized as a photodetector. Continuous FA monitoring with biochemical method is successfully conducted with high selectivity at subppb level. Owing to the improved excitation source, the detection limit is improved to 750 ppt. A real-sample test is also carried out using a photocatalytic titania. A standard gas is flowed into a cell, in which photocatalyst glasses are located, and the FA level is measured using the biosniffer. Therefore, degradation of FA by the catalytic reaction of titania is monitored as reduction of FA in real time. According to the results, it is expected to be useful in fast and convenient monitoring of indoor FA.