Wang Ya-Hong, Dong Da-Ming, Zhou Ping, Zheng Wen-Gang, Ye Song, Wang Wen-Zhong
Guang Pu Xue Yu Guang Pu Fen Xi. 2014 Oct;34(10):2863-7.
Based on sucrose solution as the research object, this paper measured the trans-reflective spectrum of sucrose solution of different concentration by the technique of near infrared spectrum in three optical path (4, 5, 6 mm). Five kinds of pretreatment method (vector normalization, baseline offset correction, multiplicative scatter correction, standard normal variate transformation, a derivative) were used to eliminate the influence of the optical path difference, and to establish model of the calibration set in combination with the PLS (Partial Least Squares)method. Five kinds of pretreatment method could restrain the inter ference of light path in varying degrees. Compared with the PLS model of original spectra, the model of multiple scattering correction combined with PLS method is the optimal model. The results of quantitative analysis of original spectra: the number of principal component PC= 6, the determination coefficient R2 = 0.891 278, the determination coefficient of cross validation R2CV = 0.888 374, root mean square error of calibration RMSEC = 1.704%, root mean square error of cross validation RMSECV = 1.827%; The results of quantitative analysis of spectra after MSC pretreatment: the number of principal component PC = 3, the determination coefficient R2 = 0.987 535, the determination coefficient of cross validation R2CV = 0.983 343, root mean square er- ror of calibration RMSEC = 0.89%, root mean square error of cross validation RMSECV = 1.05%. The correlation coefficient of the prediction set is as much as 0.976 22. root mean square error of prediction is 0.01, lesser than 0.014 36. The results show that the MSC can eliminate the influence of optical path difference, improve the prediction precision and improve the stability.
本文以蔗糖溶液为研究对象，采用近红外光谱技术在4、5、6 mm三种光程下测量了不同浓度蔗糖溶液的透反射光谱。运用矢量归一化、基线偏移校正、多元散射校正、标准正态变量变换、求导五种预处理方法消除光程差的影响，并结合偏最小二乘法（PLS）建立校正集模型。五种预处理方法均能不同程度地抑制光程干扰。与原始光谱的PLS模型相比，多元散射校正结合PLS方法的模型为最优模型。原始光谱定量分析结果：主成分数PC = 6，决定系数R2 = 0.891 278，交叉验证决定系数R2CV = 0.888 374，校正均方根误差RMSEC = 1.704%，交叉验证均方根误差RMSECV = 1.827%；MSC预处理后光谱定量分析结果：主成分数PC = 3，决定系数R2 = 0.987 535，交叉验证决定系数R2CV = 0.983 343，校正均方根误差RMSEC = 0.89%，交叉验证均方根误差RMSECV = 1.05%。预测集相关系数高达0.976 22，预测均方根误差为0.01，小于0.014 36。结果表明，MSC能消除光程差的影响，提高预测精度，增强稳定性。
