Trapping‐Enrichment Multi‐dimensional Liquid Chromatography with On‐Line Deuterated Solvent Exchange for Streamlined Structure Elucidation at the Microgram Scale

Abstract

At the forefront of chemistry and biology research, development timelines are fast‐paced and large quantities of pure targets are rarely available. Herein, we introduce a new framework, which is built upon an automated, online trapping‐enrichment multi‐dimensional liquid chromatography platform (TE‐Dt‐mDLC) that enables: 1) highly efficient separation of complex mixtures in a first dimension (1D‐UV); 2) automated peak trapping‐enrichment and buffer removal achieved through a sequence of H2O and D2O washes using an independent pump setup; and 3) a second dimension separation (2D‐UV‐MS) with fully deuterated mobile phases and fraction collection to minimize protic residues for immediate NMR analysis while bypassing tedious drying processes and minimizing analyte degradation. Diverse examples of target isolation and characterization from organic synthesis and natural product chemistry laboratories are illustrated, demonstrating recoveries above 90 % using as little as a few micrograms of material.

Deuterated Modifiers in Sub/Supercritical Fluid Chromatography for Streamlined NMR Structure Elucidation

“…20−25 A new framework recently introduced by our group, which is built upon an automated, online trappingenrichment multidimensional liquid chromatography platform (TE-Dt-mDLC) enables streamlined structure elucidation on the microgram scale. 6 Sub/supercritical fluid chromatography (SFC) has delivered impressive outcomes with a high complementarity to traditional LC approaches. 26−31 SFC has demonstrated unmatched performance in the context of chiral separations and enabled the resolution of mixtures that were challenging under LC conditions.…”

“…Delivering high purity for NMR analysis from multicomponent reaction mixtures often requires arduous fractionation workloads or multipass column separations. − The evolution of high-field magnets, small-diameter cryogenic NMR probes, and pulse sequences has facilitated the structure elucidation of complex analytes from substantially smaller-scale purifications. − As a result, chromatographic isolation on the analytical scale is now feasible, offering obvious advantages in term of speed, instrumentation, and environmental footprint.…”

“…Unambiguous structure elucidation of complex molecules requires using NMR spectra to its full extent and the utilization of high-field NMR instrumentation, delivering better signal-to-noise and spectral resolution. Combining NMR and solid-phase extraction (SPE) with LC as a desalting step has been helpful for metabolite identification. − A new framework recently introduced by our group, which is built upon an automated, online trapping-enrichment multidimensional liquid chromatography platform (TE- Dt -mDLC) enables streamlined structure elucidation on the microgram scale …”

Less Configuration and More Dimensionality: Preparative Heart-Cut Multidimensional Liquid Chromatography Based on Trapping Arrays

“…1 The identification and characterization of target components in complex mixtures has been significantly impacted by the extraordinary resolving power of multidimensional separation combined with trapping-enrichment and online deuterated solvent exchange features, which is important at nearly every stage of chemical and biological research (e.g., natural product, drug discovery and development, and -omics research). 2 As commercially available systems have become routinely available, two-dimensional liquid/gas chromatography (2D-LC, 2D-GC) has become increasingly popular among various multidimensional separation methods. 3 Improvements in the combination of multidimensional techniques with spectroscopy/spectrometry have been informative for chemical profiling, and multicomponent detection; however, these advances have not provided any benefits to purification laboratories historically.…”

“…However, mD-LCs higher than 3D-LCs at the preparative scale remain challenging. 2 Analytical and preparative 2D-LC comprise two sets of HPLC modules that are connected by switching valves and loops (or trap columns). The more dimensionality of the system, the more sets of HPLC modules needed and the more complicated the connection and control of these modules.…”