Abstract

Due to the complex nature of near-infrared (NIR) spectra, it is usually very difficult to provide quantitative interpretations of spectral data. As a consequence, careful building and validation of calibration models are of fundamental importance prior to development of useful applications of NIR technologies. For this reason, this work presents a statistical study about the NIR spectroscopy, analyzing the NIR behavior when the experimental conditions are changed. Near-infrared spectra were measured at different temperatures and stirring velocities for systems containing a pure solvent and a suspension of polymer powder in order to perform the error analysis. Then, mixtures of xylene and toluene were analyzed through NIR at different temperatures and stirring velocities and the obtained data were used to build calibration models with multivariate techniques. The results showed that the precision of the NIR measurements depends on the analytical conditions and that unavoidable fluctuations of spectral data (or spectral data variability) are strongly correlated, leading to full covariance matrices of spectral fluctuations, which has been surprisingly neglected during quantitative analyses. In particular, modeling of the xylene/toluene NIR data performed with different multivariate techniques revealed that the principal directions are not preserved when the real covariance matrix of measurement errors is taken into account.

© 2017 The Author(s)

Rapid determination of the main components of corn based on near-infrared spectroscopy and a BiPLS-PCA-ELM model

Lili Xu, Jinming Liu, Chunqi Wang, Zhijiang Li, and Dongjie Zhang
Appl. Opt. 62(11) 2756-2765 (2023)

Quantitative analysis of bayberry juice acidity based on visible and near-infrared spectroscopy

Yongni Shao, Yong He, and Jingyuan Mao
Appl. Opt. 46(25) 6391-6396 (2007)

Nondestructive detection model of soluble solids content of an apple using visible/near-infrared spectroscopy combined with CARS and MPGA

Yong Chen, Chaoyuan Cui, and Yun Wu
Appl. Opt. 60(27) 8400-8407 (2021)

Crucial aspects for the use of silicon photomultiplier devices in continuous wave functional near-infrared spectroscopy

Giovanni Maira, Massimo Mazzillo, Sebania Libertino, Giorgio Fallica, and Salvatore Lombardo
Biomed. Opt. Express 9(10) 4679-4688 (2018)

Characterization of the transmitted near-infrared wavefront error for the GRAVITY/VLTI Coudé Infrared Adaptive Optics System

Pengqian Yang, Stefan Hippler, Casey P. Deen, Wolfgang Brandner, Yann Clénet, Thomas Henning, Armin Huber, Sarah Kendrew, Rainer Lenzen, Oliver Pfuhl, and Jianqiang Zhu
Opt. Express 21(7) 9069-9080 (2013)