THz-TDS技术在淀粉中明矾含量的定量分析应用研究

Application of THz-TDS Technology in quantitative analysis of alum content in starch

应用太赫兹时域光谱(Terahertz time-domain spectroscopy,THz-TDS)技术实现淀粉中食品添加剂明矾含量的定量分析。通过太赫兹时域光谱系统获取纯淀粉和纯明矾以及其混合样品的时域光谱与频域光谱,并计算获得混合样品的吸收系数谱与折射率谱。采用偏最小二乘法在混合样品的吸收系数与样品中明矾的质量份数之间建立相应的数学模型,通过模型进行预测实现混合样品中明矾的定量分析。经模型预测结果表明混合样品的吸收系数与样品中明矾的质量份数之间的相关性达到99.1%,预测精度可以达到98.2%以上。通过实验研究采用THz-TDS系统采集样品光谱信息并通过建立PLS数学模型对混合样品的吸收系数与样品中明矾的质量份数进行建模分析能够达到定量分析淀粉中明矾含量的目的。

In this paper,Terahertz time-domain spectroscopy (THz-TDS)was used to quantitatively analyze food additive alum content in starch.The time domain and frequency domain spectra of pure starch and pure alum and their mixed samples were obtained by terahertz time-domain spectroscopy system,and the absorption coefficient spectrum and refractive index spectrum of mixed samples were calculated.A partial mathematical model is established between the absorption coefficient of mixed sample and mass fraction of alum in the sample by partial least squares method, and quantitative analysis of alum in mixed sample is predicted by the model.The model predicted the correlation between the absorption coefficient of mixed sample and mass fraction of alum was up to 99.1%.The prediction accuracy can reach more than 98.2%.Therefore,THz-TDS system can be used in collecting spectral information, and PLS mathematical model can be used in quantitatively analyze alum content in starch by absorption coefficient of mixed sample and mass fraction of alum in the sample.