多波长消荧光拉曼光谱仪的研制及应用研究

拉曼光谱技术作为探究分子、晶体及其结构特征的有力手段，具有快速、无损、样品用量小、无需前处理且适应性强等优点，已被广泛应用于食品安全、石油化工等领域。但在拉曼光谱应用中，常常受到荧光背景干扰，导致拉曼信号降低，严重的情况下拉曼信号甚至会淹没在荧光背景中。为解决拉曼技术在实际应用中荧光背景干扰的问题，从仪器角度出发，采用二色镜对多波长拉曼光谱进行光路耦合设计，研制了近红外拉曼光谱与移频差分拉曼复合一体的多波长消荧光拉曼光谱检测系统，其中近红外拉曼光谱采用1 064 nm激光光源设计，移频差分拉曼光谱选取784.5和785.5 nm两组激光光源进行时分复用，在移频差分拉曼光谱检测的同时，亦可获得两组单波长拉曼光谱数据。通过对比同步测试和分时逐次测试的强度及峰位稳定性，验证了多波长消荧光拉曼光谱仪的同步测试性能；选取了多种荧光背景强弱不同的样品，进行了单波长拉曼、近红外拉曼及移频差分拉曼光谱的对比分析。针对丙酮、乙腈等荧光背景较弱的样品，可采用单波长拉曼光谱对样品进行定量及定性分析；针对食用油、红色塑胶微粒等荧光背景与拉曼信号强度相当的样品，可采用近红外拉曼光谱对样品进行定量及定性分析；针对红酒、棕色塑胶微粒等荧光背景较强的样品，需结合近红外拉曼光谱和差分拉曼光谱对样品进行定性分析。研究表明：通过多波长消荧光拉曼光谱检测系统的研制，在常规单波长拉曼光谱技术的基础上，将两种抑制荧光干扰技术有机结合，有效扩充了应用领域及样品检测范围。

Development and Application of Fluorescence Suppression Based on Multi Wavelength Raman Spectrometer

Raman spectroscopy is a valuable method to explore the structural characteristics of molecular and crystal,which has been widely used in food safety,petrochemical and other fields due to its advantages of fast,non-destructive,small sample consumption,no pretreatment and adaptability.However,it is often interfered with by the fluorescence background when applied,which leads to the decrease of the Raman signal.The Raman signal would be submerged in the fluorescence background in the worst situation.In order to solve the problem that the fluorescence background interference in the application of Raman detection,this research have designed the optical path coupling design of multi-wavelength Raman spectrum with dichroic mirror in the instrument and developed a multi-wavelength fluorescence elimination Raman spectrum detection system combining near Red Raman spectrum and frequency shift differential Raman spectroscopy.The near-infrared Raman spectrum is designed with a 1064 nm laser source,and the frequency shift differential Raman spectrum is composed of 784.5 and 785.5 nm laser sources.By comparing the intensity and peak stability of synchronous test and successive time-sharing test,the synchronous testing performance of multi-wavelength de fluorescence Raman spectrometer was verified;The single wavelength Raman,near-infrared Raman and frequency shift differential Raman spectra,were compared and analyzed.For acetone,acetonitrile and other samples with weak fluorescence background,single wavelength Raman spectroscopy can be used for the quantitative and qualitative analysis;Near-infrared Raman spectroscopy can be used for the quantitative and qualitative analysis of samples with similar fluorescence background and Raman signal intensity such as edible oil and red plastic particles;For the samples with strong fluorescence background such as red wine and brown plastic particles,the samples can be qualitatively analyzed by near-infrared Raman spectroscopy and differential Raman spectroscopy.The results showed that based on conventional single wavelength Raman spectroscopy technology,we combined the two fluorescence interference suppression technologies through the development of multi-wavelength de fluorescence Raman spectroscopy detection system.This research will expand the range of the application field and sample detection.