基于近红外光谱法的水稻秸秆可溶性糖快速检测

采集并制备不同地域、不同品种的水稻秸秆样本288个,根据浓度梯度法,按照31的比例划分校正集与验证集。采用蒽酮硫酸比色法测定试验样本中可溶性糖含量,并采集在近红外全波段(10 000~4 000cm-1)范围内样本的近红外光谱信息。采用多元散射校正(MSC)、标准正态变量变换(SNV)、导数、S-G平滑及其组合方法对光谱进行预处理,分别运用逐步多元线性回归(SMLR)、偏最小二乘回归(PLS)和主成分回归(PCR)化学计量学算法,建立基于近红外光谱的逐步多元线性回归(SMLR)、偏最小二乘回归(PLS)和主成分回归(PCR)定量分析模型。通过比较分析,对光谱进行一阶导数预处理,建立的PLS模型效果最优,校正集实测值与预测值之间的决定系数R2C达到0.880 6,交互验证决定系数(R2CV)和验证集决定系数(R2V)分别为0.771 1、0.857 8,均方根差RMSEC、RMSECV、RMSEP分别为0.318%、0.440%、0.404%,校正集相对分析误差(RPDC)和验证集相对分析误差(RPDV)均大于2.5。结果表明,采用近红外光谱法建立的PLS模型基本可以实现水稻秸秆中可溶性糖含量的快速检测。

Rapidly detecting the content of soluble sugar in rice straw with near infrared reflectance spectroscopy

288 rice straw samples collected from different regions and varieties were used to study the feasibility of rapidly detecting the content of soluble sugar in rice straw with the near infrared reflec-tance spectroscopy (NIRS)technique.The near infrared spectral information of samples were collected within the near infrared wavelength range (10 000 -4 000 cm-1 ).The models of quantitative analysis based on near infrared spectra of stepwise multiple linear regression (SMLR),partial least squares re-gression (PLS)and principal component regression (PCR)were established using stoichiometric algo-rithm SMLR,PLS and PCR,combined with different spectral pretreatments including multiplicative scatter correction (MSC),standard normal variation transformation (SNV),derivative,S-G smoothing and their combinations.Through comparison and analysis,the optimal effect of PLS model which estab-lished by using first derivative spectra pretreatment had a determination coefficient R 2C between the cali-bration set chemical analysis values and predicted values of 0.880 6,the determination coefficient R 2CV and R 2V of 0.771 1,0.857 8,and root mean square difference RMSEC,RMSECV,RMSEP of 0.318%, 0.440%,0.404%,respectively.Both of the relative analysis error RPDC and RPDV are greater than 2.5. The results show that establishing the model by using near infrared spectroscopy,combined with PLS modeling method can quickly detect the content of soluble sugar in rice straw.