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建立白酒基酒中的己酸、乙酸的快速检测方法,通过分析白酒基酒样品的近红外光谱图,对光谱数据进行不同处理。结果表明:白酒基酒中己酸、乙酸对近红外有特异吸收,最佳预处理方法与最优波段分别为:一阶导数+减去一条直线、一阶导数+矢量归一化预处理光谱;谱区选择6 101.7-5 446 cm~(-1)和11998.9-7 501.7 cm~(-1),6 101.7~5 449.8 cm~(-1)和11 998.9~7 497.9 cm~(-1)。利用偏最小二乘法与傅里叶变换近红外光谱相结合,采用内部交叉验证法建立模型,通过对模型进行优化,己酸、乙酸校正集样品的化学值与近红外的预测值的决定系数分别为99.73%、97.00%;内部交叉验证均方根差分别为0.90、0.63 mg/100 mL;进一步对己酸、乙酸模型进行验证和评价,己酸和乙酸模型验证集的决定系数分别为99.47%、95.63%,预测标准偏差分别为1.00、1.73 mg/100 mL。结果表明建立的模型效果很好,具有较高的精密度和良好的稳定性,能满足白酒生产中己酸和乙酸的快速检测要求。
A rapid method for the determination of caproic acid and acetic acid in liquor-based liquor was established. By analyzing the near-infrared spectra of liquor-based liquor samples, the spectroscopic data were processed differently. The results showed that caproic acid and acetic acid in white spirit-based wine had specific absorption to near infrared. The best pretreatment method and optimal waveband were as follows: first derivative + minus a straight line, first derivative + vector normalized pretreatment ; 6 101.7-5 449.8 cm -1 and 11 998.9-7 497.9 cm -1 for the 6 101.7-5 446 cm -1 and 11998.9-7 501.7 cm -1, . Using partial least square method and Fourier transform near-infrared spectroscopy, the internal cross validation method was used to establish a model. By optimizing the model, the determination coefficients of the chemical value of the caproic acid and acetic acid calibration set samples and the prediction value of the near infrared were respectively 99.73% and 97.00%, respectively. The root mean square differences of internal cross-validation were 0.90 and 0.63 mg / 100 mL, respectively. Further validation and evaluation of caproic acid and acetic acid models showed that the determination coefficients of caproic acid and acetic acid model validation set were 99.47% , 95.63% respectively. The predicted standard deviations were 1.00 and 1.73 mg / 100 mL, respectively. The results showed that the established model has a good effect, high precision and good stability, and can meet the rapid testing requirements of caproic acid and acetic acid in liquor production.