Achieving Three-Dimensional Resolution in One-Dimensional Time: Multiplex 19F Chemical Shift Encoding for Profiling Amines in Complex Mixtures

Abstract

Resolving spectral crowding in complex biological matrices remains a formidable challenge in 19F NMR spectroscopy. Herein, we propose a “chemical dimensionality extension” strategy designed to overcome the inherent trade-off between data acquisition speed and spectral resolution. Through the rational design of a multiplex probe containing three chemically nonequivalent fluorine nuclei, we project the identity of a single analyte into a unique set of spatial coordinates within a pseudo-three-dimensional chemical shift space (δF1, δF2, δF3). Remarkably, this high-dimensional fingerprinting is fully realized through a rapid, standard, one-dimensional 19F NMR experiment. This chemical multiplex encoding approach exponentially increases peak capacity and effectively deconvolutes severely overlapping signals, circumventing the need for time-consuming multidimensional pulse sequences. The probe exhibits an exceptionally broad chemical shift window and high quantitative sensitivity, with a limit of detection of 0.8 μM of dopamine. To demonstrate its practical utility, we achieved the accurate quantification of dopamine (R2 = 0.999) and directly confirmed 17 endogenous amino acids from a highly congested crude extract of Ophiopogon japonicus. Ultimately, this study delivers a robust, high-throughput chemical tool for the high-resolution profiling of amine-containing metabolites, signifying a paradigm shift in NMR resolution enhancement from physical instrumentation to rational chemical design.