Absorption characteristics and quantitative contribution of overtones and combination of NIR: Method development and validation

作者：Wu Zhisheng; Du Min; Xu Bing; Lin Zhaozhou; Shi Xinyuan^*; Qiao Yanjiang

来源：Journal of Molecular Structure, 2012, 1019: 97-102.

DOI：10.1016/j.molstruc.2012.03.058

• Near-infrared spectroscopy
• Accuracy profile
• Frequency range
• Partial least squares

The present study focuses on the interpretation of the relationship between absorption characteristics and quantitative contribution in each near-infrared (NIR) frequency range. NIR spectra were measured for citric acid in each mixture solvent of water and ethanol. Accuracy profile theory was successfully utilized to validate the performance of partial least squares (PLS) models in each frequency range. It was found that saturated absorption characteristic (i.e. intensity) occurred in combination region (CR) and proportion of first combination-overtone (FCOT) region. The result of chemometric indicators, i.e. correlation coefficient (r), the root mean square errors of calibration and prediction (RMSEC and RMSEP), revealed the importance of second combination-overtone (SCOT) region in the calibration model performance. Simultaneously, it demonstrated that PLS model in FCOT or CR region could provide the lowest RMSEC and RMSEP, only when FCOT or CR region has rich transmission information. According to validation methodology parameters, i.e. relative bias, repeatability, intermediate precision, risk, lower limits of quantification (LLOQ), these results also indicated that FCOT or CR region was preferred as variables selection region, but if saturated absorption FCOT or CR region occurred, SCOT region was a better choice. In addition, the validated results testified that absorption intensities of solvent seriously interfered with model performance, especially for FCOT or CR region. Therefore, this revelation work provided a guideline for variables selection in each NIR frequency range.

• 出版日期2012-7-18
• 单位北京中医药大学