卟啉和金属卟啉配合物的合成及其在传感器中的应用

气敏材料是气体（化学）传感器的核心部位,直接影响传感器的稳定性、选择性、灵敏度和响应时间等各种性能。卟啉与金属卟啉配合物具有优良的气敏性能,目前国内外卟啉与金属卟啉传感器已应用于VOCs的检测。该文介绍了卟啉及其结构、合成方法、卟啉和金属卟啉配合物的合成及影响因素;卟啉和金属卟啉在传感器中的应用和对挥发性有机气体的检测原理。     

卟啉类分子识别载体化学传感器的近期进展

卟啉类分子由于其化学结构与配位性能方面的特征,是一类优异的化学传感器载体。金属卟啉用作电位型阴离子载体最重要的性质之一就是在轴向第五或第六配位位置选择性地与某些阴离子配位,从而导致对阴离子的选择次序呈反 Hofmeister 行为。由于卟啉环的共轭特点,卟啉周边上的取代基的电子效应将影响卟啉环内中心金属与外来离子的配位性能。卟啉类载体亦可用于光化学传感器的制备。本实验室近期较系统的研究了单卟啉与双卟啉类载体用于化学传感器的制备,取得如下的主要结果:     

卟啉传感器研究进展

卟啉类化合物因为光敏性好、性能稳定、易于修饰,采用紫外、红外、荧光、磷光、拉曼等光谱技术和电化学方法都可以检测到它的微小变化,成为传感器研究的理想模型化合物。介绍了卟啉氧传感器、卟啉二氧化碳传感器、卟啉氯化物传感器、卟啉生物传感器和卟啉其他传感器的研究进展,提出了卟啉传感器的发展方向。     

四（对—二硫杂环己烯）四氮卟啉合铜（Ⅱ）的氨敏特性

卟啉类配合物气敏特性的研究近年来有很大进展,Tredgold等~([1])报道了Cu(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Mn(Ⅱ)等金属卟啉配合物和无金属卟啉对NO_2,H_2S,CO的敏感性;文珂等~([2])研究了四个脂肪碳链的双亲性卟啉及其配合物对氨的敏感性.本文用四(对一二硫杂环乙烯)四氮卟啉合铜(Ⅱ)(即CuTTTAP)制作成厚膜旁热式电阻气敏元件.在研究了气     

基于卟啉传感器的气体检测系统的设计

针对传统气体检测方法的不足,设计了一种基于卟啉传感器的快速气体检测系统.反应室的流体仿真表明该系统检测结果具有可比性.该系统采集存储卟啉传感器与气体反应前后的图像,通过图像处理技术获得传感器阵列的颜色变化信息,将其与数据库中的记录进行匹配,得到检测结果.实验表明:该系统响应快速,能准确检测识别多种有害气体.     

卟啉枝接联吡啶用于高选择性铜离子荧光传感器的研究

该文合成了一种金属卟啉化合物,即酰胺键联接的四苯基卟啉锌和联吡啶(ZnTPPBPy),并首次将其用于识别二价铜离子.其中四苯基卟啉锌作为荧光基团,联吡啶作为识别基团.联吡啶与铜络合以后,通过光致电子转移过程,猝灭四苯基卟啉锌的荧光,这为铜离子荧光传感器的构建提供了理论基础.考察了该铜离子化学传感器的响应特性.铜离子响应的线性范围为3.2×10-7 ～1.0×10-5 mol/L,工作曲线的回归方程为log(△F/F)=9.639 1.757 log[Cu2 ].实验结果表明,在过渡金属阳离子中,除了汞离子有轻微干扰外,该传感器对铜离子具有良好的选择性.     

基于荧光卟啉传感器阵列系统的肺癌标志物检测研究

针对肺癌呼出挥发性有机气体（VOCs）中的特定标志物,提出了一种新型的基于荧光卟啉传感器阵列检测系统,并对4种肺癌呼出标志物进行检测研究。通过小波分析等数学工具对测得的荧光光谱数据进行特征提取,然后采用层次聚类、主成分分析等统计学方法对特征向量进行分析。不同体积分数的各类标志物在聚类分析中能够完全正确的聚到一起。通过主成分分析得到的前3个主成分包含了标志物的88%的信息,便能对不同类别的标志物进行识别。研究表明：该荧光卟啉传感器阵列系统能够快速有效地对不同肺癌标志物进行识别,有望在临床中得到应用。     

基于四(对-氨基苯基)卟啉的宽酸度响应范围的pH荧光化学传感器的研究

论文合成了几种卟啉化合物并考察了以它们作为荧光载体的光化学传感器对pH的响应性能.该传感器的响应是基于卟啉化合物在酸性条件下可以发生多步质子化过程而产生的荧光淬灭现象.由于具有多个质子敏感中心,以5,10,15,20-四(对一氨基苯基)卟啉[T(P-NH2)TPPH2]为载体的荧光化学传感器对pH的响应范围比5,10,15,20一四苯基卟啉的要宽得多.论文考察了膜组成对传感器响应性能的影响,并对实验条件进行了优化.经优化膜组成后的T(P-NH2)TPPH2传感器对pH的响应范围为0.50-6.30,响应时间为3min,该传感器表现出良好的可逆性和重现性,常见的阳离子对其检测pH无明显的干扰.     

卟啉传感器气体检测系统流量控制研究

针对目前卟啉传感器气体检测系统中采样气体流量控制的不足,提出了一种控制精度高、响应速度快、超调量小的流量控制系统。该系统利用增量式PID算法调整PWM脉冲信号的占空比,从而间接地改变直流电机两端电枢电压的大小,实现对采样气体流量的控制。流量控制精度为±1.5 cm3/min,且气体流量仅需15.6 s就能达到稳定。实验结果表明:控制采样气体流量,有助于卟啉传感器气体检测系统准确、快速地实现对目标气体的检测。     

四苯基卟啉薄膜/K+-交换玻璃光波导传感器的研制及其气敏性研究

利用Alder法合成了四苯基卟啉并进行了表征;用匀胶机将一定浓度的四苯基卟啉溶液做成薄膜固定在钾离子（K+）交换玻璃光波导表面,研制了高灵敏的四苯基卟啉薄膜/K+-交换玻璃光波导传感器,并对挥发性有机气体进行检测。实验结果表明,在室温下该传感器对低浓度的苯乙烯、二甲苯、甲苯等蒸气具有一定的响应,其中对二甲苯的响应最大,能检测到1×10-6（V/V0）的二甲苯蒸气。     

碳纳米管及其修饰物对挥发性有机物气敏性的研究

通过化学气相沉积(CVD)方法合成单壁碳纳米管(SWCNTs)和多壁碳纳米管(MWCNTs),并经过硝酸酸化预处理.在缩合剂N,N‘-二环己基碳化二亚胺(DCC)作用下,多壁碳纳米管经过乙二胺、十二胺和联苯胺的修饰生产新的纳米颗粒.将五种材料的悬浮液喷涂于Al2O3基底的金叉指电极上,构成气敏传感器,以甲醛、苯、甲苯、二甲苯作为测试气体,通过电化学分析仪测试他们在不同气体种类和浓度下的导电率.实验表面传感器在常温下具有较高的灵敏度和重复性,传感器之间有一定的选择性差异,可以构成传感器阵列,应用于具有复杂组分的挥发性有机气体定性和定量检测中.     

基于SAW表面气液相效应和GC分离柱的气敏传感器

限于传统涂敷敏感膜的声表面波（SAW）气敏传感器存在成膜困难和选择性差、重复性差以及再生性差等问题,本研究提出一种基于压电基底表面气体气液相转换效应机理的瑞利波传感器。在此基础上开发了一种基于瑞利声表面波传感器和气相色谱（GC）分离柱的便携式气体检测系统。最后实验论证了方案的可行性,初步的实验结果表明该系统具有分析时间短、选择性好、灵敏度高,可检测ppb（10^-9）浓度的混合VOCs以及成本低等优势,显示其在痕量挥发性有机气体检测和分析应用上有良好的潜力和前景。     

Optical VOCs detection using poly(3-alkylthiophenes) with different side-chain lengths

The use of conjugated polymers in the gas and volatile organic compounds (VOCs) detections represents an advance in the development of the electronic noses. Polythiophenes show good thermal and environmental stability, are easily synthesized and they have been studied as gas and VOCs sensors using different principles or transduction techniques. Among these techniques, optical sensing has been attracted attention, mainly due to its versatility. However, conjugated polymer-based optical sensors are still less studied. This paper describes the use of two poly(3-alkylthiophenes) for VOCs optical detection. The sensing measurements were carried out using visible spectroscopy. Both polymers showed good sensitivity to the VOCs, showing fast and reversible responses with some hysteresis, and were unable to detect hydroxylated samples. Furthermore, it was demonstrated that the thickness of polymer films influences the intensity of the optical response. Although there is similarity in the superficial composition of the polymers films, demonstrated by their surface energies, they showed significant differences in their optical properties upon exposure to the VOCs.     

基于SAW表面气液相效应和GC分离柱的气敏传感器的研究

限于传统涂敷敏感膜的声表面波（SAW）气敏传感器存在成膜困难和选择性差、重复性差以及再生性差等问题，本研究提出一种基于压电基底表面气体气液相转换效应机理的瑞利波传感器。首先建立了挥发性有机气体(VOCs)液相凝聚体薄层负载下的SAW波传模型，并仿真计算了其波传频散和波传衰减。然后在此基础上开发了一种基于瑞利声表面波传感器和气相色谱（GC）分离柱的便携式气体检测系统。最后实验论证了方案的可行性，初步的实验结果表明该系统具有分析时间短、选择性好、灵敏度高（可检测ppb浓度的混合VOCs）以及成本低等优势，因此其在痕量挥发性有机气体检测和分析应用上有良好的潜力和前景。     

固体电解质基VOCs传感器的研究进展

综述了混合位型、阻抗型和电流型三类固体电解质基挥发性有机物（VOCs）传感器在检测 VOCs方面的主要研究进展,并对固体电解质基 VOCs 传感器的发展方向和研究趋势进行了展望。     

Surface acoustic wave gas sensors based on polyisobutylene and carbon nanotube composites

Surface acoustic wave (SAW) gas sensors based on polyisobutylene (PIB) and composites (PIB and carbon nanotubes) as sensitive layers were investigated for the detection of octane and toluene (volatile organic compounds) and other atmospheric pollutants (H₂, CO, NO₂ and NH₃) at room temperature. In order to study the effect of nanotubes in the response of SAW sensors, several composites based on PIB with different percentages of multiwalled carbon nanotubes (MWNTs) were tested and compared to the response obtained from PIB SAW sensors. Sensors exhibit high responses and selectivity to volatile organic compounds (VOCs) with fast response and recovery times as well as good repeatability and reproducibility. Experimental results show as small percentages of nanotubes improve the response to octane.     

基于MWCNTs的气敏测试纸

介绍了一种简单、可直接在纸上制作的气体传感测试纸.由多壁碳纳米管(MWCNTs)在纸上摩擦,粘附的MWCNTs即为传感器的敏感层.采用相同方法分别在不同的纸张上制作传感器,并对气敏性能进行了比较,结果表明:滤纸的多孔性和粗糙的表面,可以促使其上的敏感层吸附和释放气体分子,使气体传感器在室温条件下完全恢复.传感器具有良好的重复性和稳定性.气体传感测试纸可以进一步用于挥发性有机气体(VOCs)的检测开发.     

Development and evaluation of piezoelectric-polymer thin film sensors for low concentration detection of volatile organic compounds related to food safety applications

In this study, the regioregular poly (3-hexyl thiophene) (rr-P3HT) based piezoelectric sensors were developed and evaluated to detect alcoholic volatile organic compounds (VOCs) associated with spoiled and Salmonella typhimurium contaminated packaged beef headspace. The drop coating technique was used to deposit thin films of rr-P3HT on both the sides of quartz crystal microbalance (QCM) electrode. The QCM polymer sensors were found to provide repeatable and reproducible sensor response to alcohol VOCs with a fast recovery (<2 min) at room temperature (25 °C). The principal component analysis on the sensors sensitivities was performed to discriminate the sensed alcohol VOCs, namely: 3-methyl-1-butanol from 1-hexanol. The QCM polymer sensors demonstrated selective response to low concentration of 3-methyl-1-butanol (average estimated lowest detection limit (LDL): 4.35 ppm) and to 1-hexanol (average estimated LDL: 3.20 ppm). The 30 days storage study performed on QCM sensors showed identical sensitivity responses for sensing 3-methyl-1-butanol and 1-hexanol at low concentrations.     

Polypyrrole thin film fiber optic chemical sensor for detection of VOCs

A fiber optic reflectance sensor (FORS) using Polypyrrole (PPy) conducting polymer to detect volatile organic compounds (VOCs) is demonstrated. The conventional interfacial polymerization method is used to synthesize a sensitive polypyrrole membrane, which shows relatively low roughness and high reflectivity. In general the changes in electrical properties of conductive polymers are explored in sensing applications, however their optical properties have been less explored. In the present study, we evaluate the optical properties of PPy and transfer on the end face of polymer optical fiber (POF) for the detection of VOCs. The change in the reflected optical signal from PPy upon interaction with the VOCs is systematically evaluated. The fabricated PPy FORS shows the excellent sensitivity to the VOCs under test with the detection limit up to 1 ppm.