Boosting the enantioresolution of zwitterionic-teicoplanin chiral stationary phases by moving to wide-pore core-shell particles.

A novel zwitterionic-teicoplanin chiral stationary phase (CSP), based on superficially porous particles (SPPs) of 2.7 µm particle diameter and 160 Å pore size, has been prepared and evaluated towards the enantioseparation of important classes of compounds, including chiral drugs, pesticides, and N-derivatized amino acids. The comparison with two analogous CSPs prepared on SPPs with 2.

Boosting basic-peptide separation through dynamic electrostatic-repulsion reversed-phase (d-ERRP) liquid chromatography.

The application of a novel chromatographic approach to therapeutic peptides bearing basic amino acids in their structure allowed unprecedented resolution of their related impurities (including epimeric isobaric ones), resulting in a superior analytical tool for the evaluation of the quality of these drugs in the market.

Modular and conservative procedure for the quantification of amino functionalities bonded to solid porous matrices.

Nowadays solid materials in which amino groups are linked to silica matrices through alkyl chains of different length (C18, C8, C4) are successfully employed in CO capture and storage technologies, as well as in a variety of chromatographic applications. In particular, their use as stationary phases finds remarkable success in performing HILIC separations and, in general, in the effective resolution of important compound classes (e.g.

On the effect of chiral selector loading and mobile phase composition on adsorption properties of latest generation fully- and superficially-porous Whelk-O1 particles for high-efficient ultrafast enantioseparations.

The adsorption isotherms of trans-stilbene oxide (TSO) enantiomers have been measured under a variety of normal phase (NP) mobile phases (MPs) on three Whelk-O1 chiral stationary phases (CSPs), prepared respectively on 1.8 μm and 2.5 μm fully porous particles (FPPs) and 2.

The Way to Ultrafast, High-Throughput Enantioseparations of Bioactive Compounds in Liquid and Supercritical Fluid Chromatography.

Until less than 10 years ago, chiral separations were carried out with columns packed with 5 or 3 μ m fully porous particles (FPPs). Times to resolve enantiomeric mixtures were easily larger than 30 min, or so. Pushed especially by stringent requirements from medicinal and pharmaceutical industries, during the last years the field of chiral separations by liquid chromatography has undergone what can be defined a "true revolution".

Direct analysis of chiral active pharmaceutical ingredients and their counterions by ultra high performance liquid chromatography with macrocyclic glycopeptide-based chiral stationary phases.

In this work the simultaneous separation of chiral active pharmaceutical ingredients (API) in salt form from their counterions has been performed by using different high-efficiency macrocyclic glycopeptide-based chiral stationary phases (CSPs). Not only a new zwitterionic vancomycin-based CSP has been prepared (similarly to what was done for teicoplanin) but macrocyclic selectors have also been bonded to sub-2 μm fully porous silica particles through traditional ureidic linkage to obtain versions of CSPs suitable for ultra-high performance applications. The direct separation of chiral APIs and counterions is particularly attracting since it simplifies the workflow traditionally used with reduction of analysis time and costs.

Unmatched Kinetic Performance in Enantioselective Supercritical Fluid Chromatography by Combining Latest Generation Whelk-O1 Chiral Stationary Phases with a Low-Dispersion in-House Modified Equipment.

This proof-of-concept work investigates the ultimate kinetic limits reachable in chiral supercritical fluid chromatography (SFC) with modern columns and advanced technological solutions. A commercial equipment (Waters Acquity UPC) has been in-house modified to minimize its overall extra-column variance through a series of technical adjustments including low-volume connecting tubings, reduced-volume flow cell, an in-house made external column oven, external low-dispersion injection system, and electronic temperature controller. Compared to the original (as-shipped) configuration, the extra-column variance on the low-dispersion equipment was reduced by more than 97%, from about 85 to slightly more than 2 μL (measured at 2.

New frontiers and cutting edge applications in ultra high performance liquid chromatography through latest generation superficially porous particles with particular emphasis to the field of chiral separations.

About ten years after their introduction to the market (happened in 2006), the so-called second generation superficially porous particles (SPPs) have undoubtedly become the benchmark as well as, very often, the preferred choice for many applications in liquid chromatography (LC), when high efficiency and fast separations are required. This trend has interested practically all kinds of separations, with the only exception of chiral chromatography (at least so far). The technology of production of base SPPs is advanced, relatively simple and widely available.

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

The ever-increasing need for enantiomerically pure chiral compounds has greatly expanded the number of enantioselective separation methods available for the precise and accurate measurements of the enantiomeric purity. The introduction of chiral stationary phases for liquid chromatography in the last decades has revolutionized the routine methods to determine enantiomeric purity of chiral drugs, agrochemicals, fragrances, and in general of organic and organometallic compounds. In recent years, additional efforts have been placed on faster, enantioselective analytical methods capable to fulfill the high throughput requirements of modern screening procedures.

Future perspectives in high efficient and ultrafast chiral liquid chromatography through zwitterionic teicoplanin-based 2-μm superficially porous particles.

With the aim of pushing forward the limits of high efficient and ultrafast chiral liquid chromatography, a new Chiral Stationary Phase (CSP) has been prepared by covalently bonding the teicoplanin selector on 2.0μm Superficially Porous Particles (SPPs). An already validated bonding protocol, which permits to achieve teicoplanin-based CSPs exhibiting zwitterionic behaviour, has been employed to prepare not only the 2.

Development of an improved online comprehensive hydrophilic interaction chromatography × reversed-phase ultra-high-pressure liquid chromatography platform for complex multiclass polyphenolic sample analysis.

In this study, an improved online comprehensive two-dimensional liquid chromatography platform coupled to tandem mass spectrometry was developed for the analysis of complex polyphenolic samples. A narrowbore hydrophilic interaction chromatography column (150 × 2.0 mm, 3.

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

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.

Pirkle-type chiral stationary phase on core-shell and fully porous particles: Are superficially porous particles always the better choice toward ultrafast high-performance enantioseparations?

Pirkle-type Whelk-O1 chiral stationary phase (CSP) was prepared on 2.6μm superficially porous particles (SPPs). The chromatographic behavior of columns packed with this new CSP was compared with that of columns packed respectively with 1.

Rationale behind the optimum efficiency of columns packed with new 1.9μm fully porous particles of narrow particle size distribution.

Columns packed with new commercially available 1.9 fully porous particles of narrow particle size distribution (nPSD) are characterized by extremely high efficiency. Under typical reversed phase conditions, these columns are able to generate very high number of theoretical plates (in the order of 300,000plates/m and more).

Experimental evidence of the kinetic performance achievable with columns packed with new 1.9μm fully porous particles of narrow particle size distribution.

Fully porous particles of narrow particle size distribution (nPSD) are now commercially available. In this paper, the kinetic performance of columns packed with these particles (1.9μm, 80Å pore size) has been investigated under typical reversed phase conditions by using a mixture of benzene derivatives as probes.

Ultra-fast high-efficiency enantioseparations by means of a teicoplanin-based chiral stationary phase made on sub-2 μm totally porous silica particles of narrow size distribution.

A new ultra-high performance teicoplanin-based stationary phase was prepared starting from sub-2 μm totally porous silica particles of narrow size distribution. Columns of different lengths were packed at high pressure and a deep and systematic evaluation of kinetic performance, in terms of van Deemter analysis, was performed under different elution conditions (HILIC, POM, RP and NP) by using both achiral and chiral probes. For the achiral probes, the efficiency of the columns at the minimum of the van Deemter curves were very high leading to some 278,000, 270,000, 262,000 and 232,000 plates/m in hydrophilic interaction liquid chromatography (HILIC), polar organic mode (POM), normal phase (NP) and reversed phase (RP) respectively.