Asynchronous kernel analysis for binary mixture solutions of ethanol and carboxylic acids

A quantitative index to reveal physical interactions between ethanol and carboxylic acids are derived by using self-modeling curve resolution (SMCR) kernel. SMCR is a family of chemometrics technique to deconvolute multi-component spectra into individual chemical species. By combining two-dimensional (2D) correlation spectroscopy and SMCR, a quantitative index called SMCR kernel is obtained to estimate the degree of synchronous and asynchronous correlations among chemical species. Relative relationships between ethanol and several carboxylic acids are derived from a series of SMCR kernel matrices of the binary mixture solutions. SMCR is applied to near-infrared (NIR) spectra of the mixture solutions, and several asynchronous kernel matrices are obtained. Comparison of the asynchronous kernel matrices reveals quantitative measure among hydrogen bonding of carboxylic acids strongly related to their molecular structures.