Evaluating Baseline Correction in Raman Spectroscopy: A Novel Cross‐Wavelength Correlation Approach for Low‐Maturity Organic Matter

ABSTRACT Baseline correction is a critical yet challenging task in Raman spectroscopy analysis of low‐maturity organic matter (organic material with minimal thermal alteration or metamorphism, generally with apparent peak metamorphic temperatures < 280°C), especially due to the difficulty in accurately identifying the true shape of the baseline when the spectra exhibit broad and overlapping bands. In this study, we present a novel approach to evaluate baseline correction methods by comparing the correlation of Raman spectral parameters obtained at two different excitation wavelengths (514 and 633 nm). We applied four baseline correction methods (linear, polynomial, spline, and IFORS) to the spectra of organic microfossils from a section in South China as examples and evaluated their performance based on the correlation of eight key Raman parameters between the two wavelengths. The results show that for 633 nm excitation, the linear method causes the largest errors, while the optimal baseline correction method varies among different parameters. For 514 nm excitation, all baseline methods performed similarly, with the linear method showing slightly better results. The comparative analysis of spectral parameters at two wavelengths provides a new and practical strategy for evaluating baseline correction methods in Raman spectroscopy. This methodology provides insights for improving the reliability of spectral analysis in studies of low‐maturity organic matter, offering a clearer understanding of how different baseline correction methods affect the interpretation of Raman data.