Spectral Simulation Methodology for Calibration Transfer of Near-Infrared Spectra
Spectral Simulation Methodology for Calibration Transfer of Near-Infrared Spectra
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DOI：
10.1366/000370207780466280
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发表时间：
2007-04
影响因子：
3.5
通讯作者：
Yusuf Sulub;G. W. Small
中科院分区：
文献类型：
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作者：
Yusuf Sulub;G. W. Small
描述了一种光谱模拟方法，用于从近红外光谱建立和传递多元校正模型。通过使用先前测量的摩尔吸光系数和溶剂置换因子，仅使用用光谱仪收集的需要校准模型的背景光谱来计算合成校准光谱。所得到的合成校准集与偏最小二乘回归一起使用以形成校准模型。该方法被证明用于分析在含有可变水平的丙氨酸、抗坏血酸盐、乳酸盐、尿素和三醋精的水性基质中葡萄糖的生理水平（1-30 mM）。实验测量数据从两个不同的傅里叶变换光谱仪具有不同的噪声水平和稳定性被用来评估模拟方法。使用更稳定的仪器（A），获得了性能良好的校准模型，产生0.70 mM的预测标准误差（SEP）。使用不太稳定的仪器（B），仅基于合成光谱的校准不太成功，产生1.58 mM的SEP值。对于合成光谱不能描述足够光谱方差的情况，评估增强协议，其中合成校准光谱用少量实验测量的校准样品的光谱增强。对于仪器A和B，分别用9个样品的测量光谱进行增强，将SEP值降低至0.64和0.85 mM。
A spectrum simulation method is described for use in the development and transfer of multivariate calibration models from near-infrared spectra. By use of previously measured molar absorptivities and solvent displacement factors, synthetic calibration spectra are computed using only background spectra collected with the spectrometer for which a calibration model is desired. The resulting synthetic calibration set is used with partial least squares regression to form the calibration model. This methodology is demonstrated for use in the analysis of physiological levels of glucose (1–30 mM) in an aqueous matrix containing variable levels of alanine, ascorbate, lactate, urea, and triacetin. Experimentally measured data from two different Fourier transform spectrometers with different noise levels and stabilities are used to evaluate the simulation method. With the more stable instrument (A), well-performing calibration models are obtained, producing a standard error of prediction (SEP) of 0.70 mM. With the less stable instrument (B), the calibration based solely on synthetic spectra is less successful, producing an SEP value of 1.58 mM. For cases in which the synthetic spectra do not describe enough spectral variance, an augmentation protocol is evaluated in which the synthetic calibration spectra are augmented with the spectra of a small number of experimentally measured calibration samples. For instruments A and B, respectively, augmentation with measured spectra of nine samples lowers the SEP values to 0.64 and 0.85 mM.