A Method for the Quantitative Analysis of a Key Component in Complex Mixtures Using Raman Spectroscopy Based on Peak Decomposition

Raman spectroscopy has been increasingly used in industrial production processes for analytical purposes. However, the quantitative analysis of complex mixtures based on their Raman spectra remains a problem, especially when not all of the spectra of pure components in the mixture are available. In this work, a method for the quantitative analysis of a key component in complex mixtures based on peak decomposition is introduced. The proposed method only requires the spectrum of the main component in the mixture before analysis. The spectra of the mixture are decomposed to the contributions of the main component and a group of parametric Lorentzian functions. Then, the representative peaks of the key component are extracted. Finally, a calibration model is established. This method is applied to a complex mixture containing in-xylene, o-xylene, p-xylene, ethylbenzene, methylbenzene, three trimethylbenzenes, non-aromatic hydrocarbons, etc. to determine the concentration of o-xylene in the mixture. Experiments demonstrate that the proposed method performs better than the commonly-used partial least squares (PLS), especially when the number of training samples is very small.