Caroline West

Université d'Orléans | UO

Plant seeds, as those from milk thistle (Silybum marianum), are a valuable source of nonpolar and polar compounds with potentially interesting biological activity. The main nonpolar compounds are triglycerides, which are also the main components of all vegetable oils. In addition, specific polar compounds - flavonolignans, called silymarin, have be...

Supercritical fluid chromatography (SFC) benefits from an extensive toolbox to achieve achiral or chiral separations. The most powerful tools in this box arise from the diversity of stationary phases available and the wide range of polarities achievable through manipulation of both the stationary phase and mobile phase composition. These parameters...

The chromatographic analysis of long-chain hydrophilic therapeutic peptides, with molecular weight mostly in the 3500-4500 Da range (31-34 amino acids), is explored with pressurized CO2 in the mobile phase. The optimal method was obtained on a Torus 2-PIC column, with a gradient elution of 50 to 90% co-solvent in CO2, which is relevant of enhanced-...

When starting a method development in supercritical fluid chromatography (SFC), the first step is usually to screen several stationary phases based on previous experience or simply based on what is available in the laboratory. However, as there are now a large number of stationary phases available for SFC, the choice of an adequate set of columns t...

The triglycerides composition and their respective abundance in 34 vegetable lipidic samples from 25 different natural products, most of which were edible lipid samples, were examined using ultra-high efficiency / low-pressure supercritical fluid chromatography with 5 tandem columns filled with core-shell particles, hyphenated to mass spectrometry...

In the first part of this study, a unified chromatography (UC) analysis method, which is similar to supercritical fluid chromatography (SFC) but with wide mobile phase gradients of pressurized CO2 and solvent, was developed to analyse short-chain peptides, with UV and mass spectrometry (MS) detection. In this second part, the method is compared to...

Plant‐derived natural dyes are used in a variety of formulated products, from food to cosmetics and pharmaceutics. In addition to their color, they also provide some bioactivity. While they are mostly analyzed with HPLC, supercritical fluid chromatography was also employed for several dye families, mostly for carotenoids and chlorophylls, and more...

A method to analyse short-chain bioactive peptides (MW < 800 Da) and their impurities was developed with a unified chromatography (UC) analysis, including a wide mobile phase gradient ranging from supercritical fluid to near-liquid conditions, with UV and electrospray ionization mass spectrometry detection (ESI-MS). Four stationary phases and three...

The development of automatized hyphenated systems is attractive to avoid sampling error, save time and reduce costs. Among these systems, on-line SFE-SFC allows the extraction, the separation, and the detection of molecules in an efficient, quick and eco-friendly way. After a historical introduction and explanation on the use of supercritical fluid...

Supercritical fluid chromatography (SFC) is mostly conducted with mobile phases comprising pressurized carbon dioxide and a cosolvent, whatever the exact state of the fluid. As packed‐column SFC is largely dominating the scene over capillary SFC, this chapter discusses only be related to the former. Chiral SFC has been a long‐time favorite, particu...

Modern supercritical fluid chromatography (SFC) is now a well-established technique, especially in the field of pharmaceutical analysis. We recently demonstrated the transferability and the reproducibility of a SFC-UV method for pharmaceutical impurities by means of an inter-laboratory study. However, as this study involved only one brand of SFC in...

A new approach for the asymmetric synthesis of the two enantiomers of β-phosphorus-containing α-amino acids was developed via Michael addition of secondary phosphine oxides and dialkyl phosphites to chiral Ni...

Triglycerides of vegetable oils have been extensively studied. Non‐aqueous reversed‐phase liquid chromatography and silver‐ion chromatography are most frequently used to achieve their separation. In previous works, we presented the use of supercritical fluid chromatography with long columns (75 cm) packed with fused‐core particles to provide ultra‐...

Achiral packed column supercritical fluid chromatography (SFC) has shown an important regain of interest in academic and industrial laboratories in the recent years. In relation to this increased concern, major instrument manufacturers have designed some stationary phases specifically for SFC use. SFC stationary phases have been widely examined ove...

Selective extraction is a great concern in the field of natural products. The interest is to apply specific conditions favouring the solubility of targeted secondary metabolites and avoiding the simultaneous extraction of unwanted ones. Different ways exist to reach selective extractions with suited conditions. These conditions can be determined fr...

Biomolecules like proteins, peptides and nucleic acids widely emerge in pharmaceutical applications, either as synthetic active pharmaceutical ingredients, or from natural products as in traditional Chinese medicine. Liquid-phase chromatographic methods (LC) are widely employed for the analysis and/or purification of such molecules. On another hand...

In this project, we aimed at analysing flavonoid-type compounds with unified chromatography (joining supercritical fluid chromatography and enhanced fluidity liquid chromatography with carbon dioxide-methanol mobile phases covering a wide range of compositions) and diode-array and electrospray ionization mass spectrometric detection (UC-DAD-ESI-MS)...

The role of individual functional groups has been assessed with regard to surface charge and chromatographic retention. Coatings were prepared from various fragments of the chiral zwitterionic materials Chiralpak ZWIX(+) and ZWIX(-). The different chromatographic ligands allowed fine tuning of the surface charge. Chiralpak ZWIX phases showed strong...

Amino acids are most often analyzed in reversed-phase liquid chromatography after a derivatization procedure to render them sufficiently hydrophobic and detectable with UV or fluorimetric detection. Simpler methods should be possible to avoid additional chemical reactions. We present an improved method to analyze free amino acids with unified chrom...

Chiralpak ZWIX(+) and ZWIX(-), are brush-type bonded-silica chiral stationary phases (CSPs), based on complex diastereomeric Cinchona alkaloids derivatives bearing both a positive and a negative charge. In the present study, we aimed to improve the understanding of retention and enantioseparation mechanisms of these CSPs employed in supercritical f...

This paper presents a review of the recent literature covering separations of enantiomers achieved with supercritical fluid chromatography (SFC) or subcritical fluid chromatography. First of all, the recent progress in SFC technology are explained in relation to chiral separations. Mobile phases and operating conditions mostly encountered in curren...

Macrocyclic glycopeptides have been used as chromatographic stationary phases for over twenty years, particularly for their ability to separate enantiomers. While they are mostly used with buffered aqueous liquid mobile phases, they can also be used in supercritical fluid chromatography (SFC) with mobile phases comprising pressurized carbon dioxide...

Supercritical fluid chromatography (SFC) employs fluids that are raised above their critical pressure (Pc) and critical temperature (Tc) as mobile phases. Carbon dioxide is the fluid most commonly used as a mobile phase for SFC. It is capable of solvating nonpolar and moderately polar analytes. Cosolvents and additives are combined to CO2 to increa...

In this project, we aimed at analyzing native (or free) amino acids with supercritical fluid chromatography coupled to mass spectrometric detection, with modern instruments and methods, and maintaining as simple a mobile phase as possible to ensure applicability of the method. The purpose was twofold: (i) a generic method allowing for satisfactory...

A stressed degradation (oxidation) was employed to produce metabolites from an active pharmaceutical ingredient (API) with large molecular weight (about 900 g/mol). An analytical chromatographic method was desired to compare the products generated by different degradation methods while a multi-gram-scale preparative chromatographic method was neces...

The mobile phases employed in current practice of supercritical fluid chromatography (SFC) are usually composed of a mixture of pressurized carbon dioxide and a co-solvent. The co-solvent is most often an alcohol and may contain a third component in small proportions, called an additive (acid, base or salt). In the first part of this series, the ef...

2-Ethylpyridine-bonded silica is one of the most famous stationary phases employed in supercritical fluid chromatography, especially for the analysis of basic compounds and even without an additive in the mobile phase. In the present paper, we present the synthesis and characterization of three original stationary phases based on poly(vinylpyridine...

A thorough knowledge of the composition of natural products is desired in many application fields, for instance: for pharmaceutic and cosmetic applications where the identity of active species must be determined, or in traditional medicine and foodomics where the quality must be strictly controlled. This chapter describes the analysis of natural pr...

Many different sorts of bonded phase chemistries may be used in high-performance liquid chromatography (HPLC) in the reversed-phase mode: C8, C18 (type A or B), polar-embedded C18, phenyl, pentafluorophenyl, or cyanopropyl. To assess their retention and selectivity properties, chromatographic tests exist. The data obtained from these tests may be p...

Supercritical fluid chromatography (SFC), which employs pressurized carbon dioxide as the major component of the mobile phase, has been known for several decades but has faced a significant resurgence of interest in the recent years, thanks to the development of modern instruments to comply with current expectations in terms of robustness and sensi...

To assess the presence of prohibited anabolic substances used to promote growth in livestock, calf urine is the most relevant matrix. However, the sample preparation methods (required to remove unwanted matrix components and fractionate isobaric species that may be unresolved by gas chromatography- mass spectrometry GC/MS) are long and complex. In...

Mixed-mode HPLC (MM-HPLC), combining different interactions or retention modes in a single column, can be an interesting alternative to reversed-phase HPLC, notably to achieve the combined retention of polar and non-polar species. In the present fundamental study, we have selected one bimodal stationary phase allowing for both reversed-phase and we...

The development of new active pharmaceutical ingredients (API) requires accurate impurity profiling. Nowadays, reversed-phase HPLC (RPLC) on C18 stationary phase is the method of first choice for this task and usually employed in generic screening methods. However, this method sometimes fails, especially when the target analyte is not sufficiently...

The characterization of chromatographic columns is of interest to column manufacturers willing to define the properties of the material they have designed, and to chromatographers looking for adequate columns to suit their separation needs. Nonchromatographic methods provide limited information, while chromatographic methods provide information on...

Thirteen pairs of enantiomers belonging to the same structural family (phenylthiohydantoin-amino acids) were analyzed on two polysaccharide chiral stationary phases, namely, tris-(3,5-dimethylphenylcarbamate) of amylose (Chiralpak AD-H) or cellulose (Chiralcel OD-H) in supercritical fluid chromatography with a carbon dioxide/methanol mobile phase (...

To achieve the most complete impurity profiling of synthetic drugs with a single chromatographic technique, high resolution is required, which may be gained with a combination of high efficiency and versatile selectivity, allowing to separate most similar analytes. Compared to a single-column chromatographic method, coupling complementary stationar...

Asymmetric sulfoxides is a particular case of chirality that may be found in natural as well as synthetic products. Twenty-four original molecules containing a sulfur atom as a centre of chirality were analyzed in supercritical fluid chromatography on seven polysaccharide-based chiral stationary phases (CSP) with carbon dioxide – methanol mobile ph...

The mobile phases employed in current supercritical fluid chromatography (SFC) are usually composed of a mixture of pressurized carbon dioxide and a co-solvent. The co-solvent is most often an alcohol and may contain a third component in small proportions, called an additive (acid, base or salt). The polarity of such mobile phase compositions is he...

Part V of this series takes a closer look at discriminant analysis (DA). Discriminant analysis is supervised method, meaning that it involves some previous knowledge of your samples.

Analysis and production of enantiomerically pure compounds is a major topic of interest when active pharmaceutical ingredients are concerned. Enantioselective chromatography has become a favourite both at the analytical and preparative scales. High-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) are dominating...

Impurity profiling of organic products synthesized as possible drug candidates represents a major analytical challenge. Complementary analytical methods are required to ensure that all impurities are detected. Both high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) can be used for this purpose. In this study,...

Nine commercially available polar and aromatic stationary phases were characterized under supercritical fluid chromatographic (SFC) conditions. Retention data of 64 pharmaceutical compounds was acquired to generate models based on the linear solvation energy relationship (LSER) approach. Previously, adaptation of the LSER model was done in liquid c...

This new series of very short tutorials explains, in the simplest manner, how statistics can be both useful and accessible, even for chromatographers who normally find statistics difficult. Here in part I, we explain how to collect and examine your data.

The interest of pharmaceutical companies for complementary high-performance chromatographic tools to assess a product's purity or enhance this purity is on the rise. The high-throughput capability and economic benefits of supercritical fluid chromatography, but also the "green" aspect of CO2 as the principal solvent, render supercritical fluid chro...

Sub- and supercritical fluid chromatography (SFC) are the terms currently accepted to describe chromatography with carbon dioxide - based mobile phases . While capillary SFC was first developed in the early years, packed column SFC has now taken the lead and will be described in this chapter. The characteristics of the fluids employed in SFC (low v...

Sub- and supercritical fluid chromatography (SFC) are the terms currently accepted to describe chromatography with carbon dioxide - based mobile phases . While capillary SFC was first developed in the early years, packed column SFC has now taken the lead and will be described in this chapter. The characteristics of the fluids employed in SFC (low v...

Supercritical fluid chromatography (SFC) is a very useful tool in the purpose of impurity profiling of drug candidates, as an adequate selection of stationary phases can provide orthogonal separations so as to maximize the chances to see all impurities. The purpose of the present work is to develop a method for chemical purity assessment. The first...

Caroline West, the winner of the 2015 LCGC Emerging Leader in Chromatography award, has a diverse set of scientific interests in high performance liquid chromatography (HPLC), supercritical fluid chromatography (SFC), hydrophilic-interaction chromatography (HILIC), and enantioselective separations-but all are primarily focused on the fundamentals o...

Chiral chromatographic techniques in the liquid, gas or supercritical fluid state (HPLC, GC and SFC) using chiral stationary phases (CSPs) are widely used for analytical and preparative separations of enantiomers. Since a versatile CSP capable to achieve any enantioseparation does not exist yet, huge efforts have been done to build predictive model...

This paper presents a review of the literature covering separations of enantiomers achieved with supercritical fluids. Supercritical fluid chromatography (SFC) is the main technique represented but chiral extraction (chiral SFE) and simulated moving bed (SMB) are also present. First of all, a historical view of the technique is presented. Then stat...

Stationary phases containing pyridine, phenol, aniline and morpholine groups were synthesized using copper (I)-catalyzed azide-alkyne cycloaddition click reactions. The backbone of the stationary phases was aminopropyl silica. The stationary phases were evaluated in packed-column supercritical fluid chromatography (pSFC) with acidic and basic solut...

Since the expiration of the patent protection of Chiralcel OD, similar chiral stationary phases (CSPs), all based on the same chiral selector, have been introduced on the market with the promise to reproduce or improve the performance of the original cellulose tris-(3,5-dimethylphenylcarbamate) CSP. We report here-in an in-depth evaluation of four...

New and original heterocyclic α-enamido phosphine chiral solutes were prepared: four structurally similar racemates with the chirality center placed on the phosphorus atom, and four other related pairs of enantiomers with chirality borne by the carbon atoms of the phospholane ring. The structural variations were placed on an aliphatic heterocycle (...

This article investigates the influence of liquid mobile phase composition on the response measured in electrospray ionization-mass spectrometry (ESI-MS) for 12 selected neurotransmitters. The aim was to find the optimal conditions to achieve sufficient limits of detection (LOD) that would permit their detection by liquid chromatography-tandem mass...

The use of anabolic substances to promote growth in livestock is prohibited within the European Union as laid down in Directive 96/22/EC. Nowadays, efficient methods such as steroid profiling or isotopic deviation measurements allow to control natural steroid hormones abuse. In both cases, urine is often selected as the most relevant matrix and, du...

The indole ring is present in many pharmaceutically active compounds, as in MaxiPost™ (or BMS-204352), an active pharmaceutical ingredient for post-stroke neuroprotection. Two different fluoro-oxindole-type chiral solutes derived from MaxiPost were prepared. The structural modification was placed on the NH indole function, which is probably taking...

Twenty-six resins from six botanical sources belonging to the class Magnoliopsida were compared based on gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry data. The extracts were analysed by GC after silylation and by reversed phase LC combined with atmospheric pressure photoionisation (APPI) mass spectrometry. The ch...

The use of anabolic agents in food producing animals is prohibited within the EU since 1988 (96/22/EC directive). However, steroid hormones may be still fraudulently employed for anabolic purpose. Nowadays, efficient method based on isotopic deviation measurement (δ13C) to confirm the illegal use of natural steroids is applied in laboratories in ch...

All stationary phase chemistries are useful to achiral packed-column supercritical fluid chromatography (pSFC), but the majority of recent applications are based on polar stationary phases of the type used in normal-phase HPLC. Some manufacturers have recently introduced pSFC-tailored stationary phases, while others simply advocate the use of selec...

Due to the renewal of the use of supercritical fluid chromatography (SFC), the coupling of SFC with evaporative light scattering detection (ELSD) needs to be revisited. Indeed, SFC and ELSD apparatus have evolved, while understanding of the nebulisation process has improved. This detector, first developed for polymer analyses can be used for a lot...

This paper investigates classification models for packed columns used in supercritical fluid chromatography (SFC). Forty‐eight columns of varied stationary phase chemistries available on the market are evaluated. The retention factors of 134 selected test compounds are used to compute hierarchical cluster analysis (HCA), principal component analysi...

The use of an evaporative light scattering detector (ELSD) with high performance liquid chromatography (HPLC) has been well documented. However, because the mobile phase is nebulized to produce droplets the use of supercritical fluids as the mobile phase with an ELSD is also favourable because the fluid depressurizes before the detector entrance, w...

We report herein the Pd-catalyzed P-C cross-coupling reaction between enol phosphates and secondary phosphane-borane complexes or phosphane oxides. The reaction was performed under mild conditions, owing to Pd activation of the P-H bonds of the phosphane-boranes (or phosphane oxides) and to the powerful enol phosphate coupling reagents. New useful...

In a recent paper published by Mitchell et al. in this journal, some results obtained in supercritical fluid chromatography and interpreted with the solvation parameter model to characterize interactions for "novel stationary phases" were surprising to us. Indeed, we had already published results for most of the stationary phases reported, but, exc...

Two commercial stationary phases possessing a sulfobetaine zwitterionic bonded ligand (ZIC-HILIC and Nucleodur HILIC) were compared under hydrophilic interaction chromatographic (HILIC) conditions. First of all, the separation of 12 model compounds chosen among neurotransmitters and presenting a diversity of ionization states (anionic, cationic and...

The importance of chiral interactions for both preparative and analytical separations, particularly for pharmaceutical applications, is underlined by numerous publications in this field. Here, for the first time, a team of experienced analysts from industry and academe presents a comprehensive review of the various mechanisms that result in enantio...

Supercritical carbon dioxide (SC-CO2) extractions of Brazilian cherry (Eugenia uniflora L.) were carried out under varied conditions of pressure and temperature, according to a central composite 22 experimental design, in order to produce flavour-rich extracts. The composition of the extracts was evaluated by gas chromatography coupled with mass sp...

In this series of papers, we use a systematic approach to investigate the factors responsible for enantio-recognition in supercritical fluid chromatography (SFC) on chiral stationary phases (CSPs). In this first part, the interactions contributing to the retentions of the achiral solutes are measured with a modified version of the solvation paramet...

In this second part of our work on enantioselective supercritical fluid chromatography (SFC), we investigate the factors participating in the chiral recognition process on tris-(3,5-dimethylphenylcarbamate) of amylose and cellulose chiral stationary phases (CSPs). 135 racemates with diverse structures were analysed under identical SFC conditions on...

This paper presents the comparison between 12 hydrophilic interaction liquid chromatography columns that are commercially available. The main factors influencing the retention and selectivity toward 12 neurotransmitters for these different HILIC systems have been studied. For additional information, the retention data have been analyzed statistical...

Separation of furocoumarins has become of a great interest for cosmetic industry and human health, since the recent directive of the European Union. Furocoumarins are a class of compounds presenting varied substituents linked mainly in two positions to an identical skeleton made by a furan ring bonded to a coumarin nucleus (Psoralen). The substitue...