水体中微量苯系污染物的便携式近红外快速检测关键技术研究

Real-time and fast detection of environmental pollutants is reliable basis for making emergency measures. The application prospect of near infrared spectroscopy (NIRS) have been greatly accepted for fast, in-situ and on-line analysis. However,There are two application restrictions for NIRS. Firstly, conventional commercial NIRS instruments adopted halogen lamp and complicated splitting system obtain continuous spectra which makes the instruments cost much, harsh environmental requirements and hard to taken and field analysis. Secondly, higher detection limits of NIRS makes the method unsuitable to analyze environmental pollutants which always exist at micro or trace levels. In the project, array type laser diodes (LDs) and light emitting diodes (LEDs) which can produce multi-wavelength are used for detecting environmental pollutants.The portable system contains no light splitting mechanism, and makes the sources and splitting mechanism into one unit. Special sampling accessory is designed for enrichment of micro BETX environmental pollutants and detection of analytes. Selection methods of emission wavelengths for the array type LDs and LEDs are studied. Driving and detection circuits are designed. Efficient enrichment fillers and special detection accessories are studied. Modelling algorithms used for discrete spectral information extraction are studied. Finally, the theories and experimental verifications of principles, schemes and methods for portable NIR trace components detection system are completed. It can offer a reliable technological scheme for portable photometers.

环境污染物的实时快速检测是制定应急措施的依据。近红外光谱分析方法快速、原位和在线分析等特点使其在环境分析中具有极大的应用前景，然而该方法的应用存在如下局限：（1）常规的近红外仪器采用卤钨灯光源和结构复杂的分光机构得到连续光谱，造价高，而且对环境的要求较苛刻，不便于携带和现场分析；（2）环境污染物常以微量或痕量级存在，近红外分析方法较高的检测限无法满足检测要求。本项目采用阵列半导体激光器或多个发光二极管产生多波长用于环境中微量苯系污染物的检测，系统无分光机构，将光源和分光系统合二为一，并针对微量苯系环境污染物研制适合于微量组分富集和检测的专用检测附件。研究激光器和二极管发射波长选择方法、设计检测系统的驱动电路和检测电路、研究高效的污染物富集材料和专用测量附件，研究离散型光谱信息建模算法，最终完成微量组分便携式近红外检测系统原理、方案和方法的理论和试验验证。为开发便携式仪器提供可靠的技术方案。

近红外光谱分析方法快速、原位和在线分析等特点使其在分析y应用中具有极大的应用前景，然而该方法的应用存在如下局限：（1）常规的近红外仪器采用卤钨灯光源和结构复杂的分光机构得到连续光谱，制造成本较高，而且对环境的要求较苛刻，不便于携带和现场分析；（2）在进行微量或痕量组分分析时，近红外分析方法较高的检测限无法满足检测要求。因此，研究适用于微量组分现场快速分析的便携式近红外光谱仪可以极大的拓展近红外光谱的应用领域。按照项目计划要求，项目组分别在便携式近红外检测系统和样品采集附件的研制、新型化学计量学方法研究、光谱仪测控软件系统开发和近红外光谱的应用研究4方面开展了相关工作。通过自主研发和器件集成的方式完成了包括便携式近红外土壤养分检测仪、基于3波长LD光源的水分测定仪、便携式水果品质检测仪及微型纺织品成分检测仪等5款便携式近红外光谱仪样机及部分测样附件的研制，并开发了相应的光谱仪控制和信息分析软件系统；采用树脂吸附富集和分段建模算法提高微量组分的分析精度；在新型计量学方法研究方面先后探索了局部线性嵌入和改进的连续投影等算法在光谱信息提取和建模中的应用，并得到了较好的分析精度；在近红外光谱应用方面先后采用近红外光谱结合不同的光谱预处理方法、变量筛选方法以及PLS、SOM和SVM等定量定性分析方法对食醋、食用植物油、木材、转基因食品的成分和种类进行分析鉴别。通过项目的实施，形成了完备的便携式近红外仪器开发的技术资料，进一步拓展了近红外光谱的应用领域，圆满的完成了项目任务。