基于色相算法的表面等离子体共振成像传感器对苯并芘的敏感特性

报道了一种用于原位探测水中苯并芘的彩色表面等离子体共振成像(SPRI)传感器,该传感器既能提供直观的图像信息,又能借助色相算法定量分析待测物质的浓度及其吸附/脱附过程。首先利用自制的波长-图像同步检测型SPR传感器测试了裸金薄膜芯片在不同入射角下的共振波长和共振图像,然后利用色相算法建立了SPR共振波长与图像色相的依赖关系,基于该依赖关系获得了SPR传感器最佳色相灵敏度对应的起始共振波长约为650 nm;另一方面,制备了聚四氟乙烯涂覆的SPR传感芯片,基于聚四氟乙烯膜对水中苯并芘的可逆富集作用实现了苯并芘的原位快速探测。实验取得以下4个结果:(1)在20-100 nmol?L-1浓度范围内彩色SPR图像的平均色相值随着苯并芘浓度的升高线性减小;(2)对100 nmol?L-1的苯并芘的响应和恢复时间分别约为7和5 s;(3)由于聚四氟乙烯膜的厚度大于SPR消逝场穿透深度,检测结果不受溶液折射率影响;(4)在聚四氟乙烯敏感膜厚度较小且不均匀的情况下,传感器容许获取敏感膜的不同厚度区域对苯并芘的色相灵敏度。实验结果有力地证明了这种彩色SPR图像传感器在生化物质检测中具有良好的应用前景。

Benzo[a]pyrene Sensing Properties of Surface Plasmon Resonance Imaging Sensor Based on the Hue Algorithm

A colorful surface plasmon resonance imaging sensor for the in-situ detection of benzopyrene (BaP) in water is presented in this paper. The sensor can provide intuitive image information and can also quantitatively analyze the concentration and adsorption/desorption processes of the analyte by combining the hue algorithm. Both the resonance wavelengths and resonance images for a bare gold film chip were obtained at different incident angles using a home-made surface plasmon resonance (SPR) sensor that possesses wavelength-interrogating and imaging capabilities. The relationship between the resonance wavelength and the average hue of the color image was established based on the hue algorithm. From this relationship, the initial resonance wavelength at which the SPR sensor can provide optimal hue sensitivity was derived, which was ~650 nm. Polytetrafluoroethylene (PTFE)-coated SPR sensor chips were prepared for the in-situ rapid detection of BaP in water based on the reversible enrichment of BaP molecules in the PTFE film. The results showed that: (1) the average hue of the SPR color image decreases linearly as BaP concentration increases from 20 to 100 nmol·L^-1; (2) both the response time and recovery times of the SPR sensor for 100 nmol·L^-1 BaP are 7 and 5 s, respectively; (3) since the thickness of the PTFE filmis greater than the penetration depth of the surface plasmon field, the BaP detection is not affected by the refractive index of the solution sample; and (4) in the case of a non-uniform PTFE film, the sensor allows to determine the hue sensitivities for equal-thickness microscale areas of the sensing film. The experimental results show that this type of colorful SPR imaging sensor has widespread applicability for chemical and biological detection.