用于食品成分分析的双探测器近红外光谱仪

Near infrared spectrometer with double detectors for food component analysis

研制了双探测器结构的滤光片型漫反射近红外光谱仪。用分束镜将单色光分成两束,一束光直接被一个探测器接收,另一束光经过积分球后照射到样品上,样品的漫散射光被积分球上的另一个探测器接收。将两个探测器的测量值相比较,计算出样品的吸光度。应用该仪器检测了漫反射标准板的漫反射率,测量值与标称值的相关系数平均为0.995,标准偏差平均为0.01。另外,使用该仪器测定了奶粉、牛奶及酱油相关成分含量,近红外光谱与奶粉的蛋白质和脂肪含量的相关系数>0.9,与酱油及原奶的相关成分含量的相关系数>0.8。检测结果表明,自制的双探测器结构滤光片型近红外光谱仪可以准确获得样品的漫反射率。

A Near Infrared （NIR） diffuse spectrometer with double detectors was introduced to improve the stability of spectral signal. The monochromatic beam was separated into two light beams by a splitter in this spectrometer. One light beam was collected directly by a detector, the other was irradiated on the sample＇s surface after passing through an integrating sphere. The diffuse light of the sample was collected with another detector on the integrating sphere. Finally, the values of the two detectors were compared to obtain the absorbency. The instrument was used to detect the diffuse reflectivity of standard diffuse reflectance surface. Detected results show that the mean correlation coefficient between the measured diffuse reflectance and the real values is 0. 995. The mean standard deviation is 0.01. In addition, the instrument was used to measure some components including of milk powder,milk and soy sauce also,the correlation coefficients of calibration are over 0.8. It concludes that the homemade spectrometer can get the right diffuse reflectivity,and can be used in food component analysis.