Li Jingwei, Jiang Wentao, Yao Xinli, Cai Fuhong, He Sailing
Appl Opt. 2018 Aug 1;57(22):6276-6282. doi: 10.1364/AO.57.006276.
We present a fast hyperspectral line-scan fluorescence imaging system to verify the feasibility of quantitative fluorescence authentication of powders. Vanillin, which is restricted for use in milk powder, especially in milk powder for infants, is mixed with milk powder in different mass concentrations (5%, 10%, 30%, 50%, 70%, and 90%). Mixed powders are located on a motorized linear stage. A 405 nm line laser is utilized to excite the fluorescence of the sample. Based on galvo scanning, we can generate a laser line with high spatial resolution and high-intensity density on the samples. An imaging spectrometer with a complementary metal-oxide semiconductor (CMOS) camera as detector is built. The spectral range of the spectrometer is 365-810 nm, with about 1 nm spectral resolution. One snapshot of the CMOS can acquire the fluorescent spatial and spectral information of a line region in 100 ms. By scanning the motorized linear stage, we obtain the fluorescence hypercube of the sample. A 100×1926×1216 hypercube, which covers an area of 15 mm×5 mm, is obtained in 50 s. The imaging speed can be enhanced further by increasing the intensity of the excitation laser and the sensitivity of the area camera. Fully constrained least squares, a linear spectral mixture analysis, is utilized to analyze the hypercube obtained by our homemade imaging spectrometer, thus obtaining the pixel concentration of vanillin in each mixed powder. Linear regression analysis is used for the pixel concentration and mass concentration of vanillin. A linear relationship with coefficient of determination R equal to one is observed, which demonstrates the capability of fluorescence hyperspectral quantitative analysis in powders.
我们展示了一种快速高光谱线扫描荧光成像系统，以验证粉末定量荧光鉴别方法的可行性。将禁止用于奶粉（尤其是婴幼儿奶粉）中的香兰素与奶粉按不同质量浓度（5%、10%、30%、50%、70%和90%）混合。混合后的粉末放置在电动线性平台上。使用405 nm线激光激发样品的荧光。基于振镜扫描，我们可以在样品上生成具有高空间分辨率和高强度密度的激光线。构建了一个以互补金属氧化物半导体（CMOS）相机作为探测器的成像光谱仪。光谱仪的光谱范围为365 - 810 nm，光谱分辨率约为1 nm。CMOS相机的一次快照可在100 ms内获取线区域的荧光空间和光谱信息。通过扫描电动线性平台，我们获得了样品的荧光超立方体。在50 s内获得了一个100×1926×1216的超立方体，其覆盖面积为15 mm×5 mm。通过提高激发激光的强度和面阵相机的灵敏度，成像速度可以进一步提高。利用完全约束最小二乘法（一种线性光谱混合分析方法）对我们自制的成像光谱仪所获得的超立方体进行分析，从而得到每种混合粉末中香兰素的像素浓度。对香兰素的像素浓度和质量浓度进行线性回归分析。观察到决定系数R等于1的线性关系，这证明了荧光高光谱定量分析在粉末中的能力。
