Calibration of multiplexed fiber-optic spectroscopy

Zeng-Ping Chen, Li-Jing Zhong, Alison Nordon, David Littlejohn, Megan Holden, Mariana Fazenda, Linda Harvey, Brian McNeil, Jim Faulkner, Julian Morris

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


Large-scale commercial bioprocesses that manufacture biopharmaceutical products such as monoclonal antibodies generally involve multiple bioreactors operated in parallel. Spectra recorded during in situ monitoring of multiple bioreactors by multiplexed fiber-optic spectroscopies contain not only spectral information of the chemical constituents but also contributions resulting from differences in the optical properties of the probes. Spectra with variations induced by probe differences cannot be efficiently modeled by the commonly used multivariate linear calibration models or effectively removed by popular empirical preprocessing methods. In this study, for the first time, a calibration model is proposed for the analysis of complex spectral data sets arising from multiplexed probes. In the proposed calibration model, the spectral variations introduced by probe differences are explicitly modeled by introducing a multiplicative parameter for each optical probe, and then their detrimental effects are effectively mitigated through a "dual calibration" strategy. The performance of the proposed multiplex calibration model has been tested on two multiplexed spectral data sets (i.e., MIR data of ternary mixtures and NIR data of bioprocesses). Experimental results suggest that the proposed calibration model can effectively mitigate the detrimental effects of probe differences and hence provide much more accurate predictions than commonly used multivariate linear calibration models (such as PUS) with and without empirical data preprocessing methods such as orthogonal signal correction, standard normal variate, or multiplicative signal correction.

Original languageEnglish
Pages (from-to)2655-2659
Number of pages5
JournalAnalytical Chemistry
Issue number7
Early online date7 Mar 2011
Publication statusPublished - 1 Apr 2011


  • near-infrared spectroscopy
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