Recent advancements and future directions of superficially porous chiral stationary phases for ultrafast high-performance enantioseparations

Abstract

This review focuses on the use of superficially porous particles (SPPs) as chiral stationary phases for ultra-high performance liquid enantioseparations. In contrast to what happened in achiral separations where core-shell particles invaded the market, the introduction of SPPs in chiral liquid chromatography (LC) has been relatively recent. This is due in part to the technical difficulties in the preparation of these phases, and in part to scarce understanding of mass transfer phenomena in chiral chromatography. As a matter of fact, nowadays, the development of superficially porous CSPs is still in its infancy. This paper covers the most recent advancements in the field of core-shell technology applied to chiral separations. We review the kinds of chiral selectors that have been used for the preparation of these phases, by discussing the advantages of chiral SPPs over their fully-porous counterparts for high efficient high throughput enantioseparations. Notwithstanding the apparently obvious advantages in terms of the mass transfer of chiral SPPs, some critical aspects that could impact their development are presented.

Enantioselective ultra high performance liquid and supercritical fluid chromatography: The race to the shortest chromatogram

“…The progress in this field has been already reviewed in Refs. , attesting the main interest of the topic.…”

Investigation of mass transfer properties and kinetic performance of high‐efficiency columns packed with C18 sub‐2 μm fully and superficially porous particles

“…Moreover, k 1 is connected to the more often employed phase retention factor, k (=( − t 0 )/, being t 0 the void time), through the following relationship [11, 52]: …”

“…However, due to the very reduced surface area, monoliths are in general less retentive than packed beds. The introduction of second‐generation superficially porous particles (SPPs), or alternatively called core–shell particles, has undoubtedly marked the advent of the most important alternative to sub‐2 μm FPPs [7–15]. Produced with innovative techniques that allow to obtain particles characterized by very narrow particle size distribution (nPSD), these materials combine the benefit of a high permeability (allowing the use of SPP columns on common HPLC instruments) and very small band broadening [16, 17].…”

Synthesis of enantiomerically pure alcohols and amines via biocatalytic deracemisation methods

“…Chiral alcohols 1,2 and amines [3][4][5][6][7] are pivotal building blocks for the manufacturing of chemical products such as agrochemicals, flavours, fragrances and pharmaceutical. This predominance of chiral alcohol and amine moieties has stimulated the development of a multitude of synthetic and physicochemical approaches including chromatographic separation of racemates on high-performance porous chiral stationary phases, 8 enantioselective resolution using resolving agents 9 and stereoselective synthesis from ketones and imines. [10][11][12][13][14][15] Due to their inherent homochirality, enzymes play an important role as catalysts in the synthesis of optically active alcohols and amines.…”