HPLC

When selecting new candidates for multifaceted analytical separation science jobs, we rarely find an exact match. So what should we be looking for in job candidates?

At ChromTalks, experienced speakers shared mistakes made during their careers.

Technology improvements have reignited interest in open-tubular LC, which promises high efficiency, low backpressure, and more environmentally sustainable separations.

In the final article of this series on extracolumn dispersion, we look at elution mode, post-column flow splitting, and a free calculator to use during method development.

I do not believe in classic linear separations anymore—further, I think separations science is wildly underdeveloped and under-appreciated.

Per- and polyfluoroalkyl substances (PFAS) in surface water have become a major concern due to their persistency and toxicity. We recently spoke to Stefan Van Leeuwen and Bjorn Berendsen of Wageningen Food Safety Research (WFSR), in The Netherlands, about their novel research into non-targeted PFAS screening using an LC–HRMS method with fragment ion flagging.

This is the first article in a four-part series exploring the quantitative assessment of drugs and their metabolites in biological fluids (such as blood, plasma, and urine) and tissue homogenates using liquid chromatography–mass spectrometry (LC–MS).

The stochastic theory of chromatography allows one to connect mathematics to separation science in an intelligible form. We take a “walk” through the column at the level of an Ant-Man, where we can see that chromatography is mathematics and mathematics is chromatography!

In recent articles, we reviewed the basic concepts of extracolumn dispersion and how this phenomenon can impact the quality of an LC separation. We now specifically discuss the effects of dispersion that can occur due to tubing and detectors.

Using ion mobility, analytes that have the same molecular mass can be separated by their shape, centers of mass, and collision cross section, but challenges such as ion loss can still occur. A new development in ion mobility separation, high-resolution ion mobility (HRIM), addresses such problems, and is particularly well suited to challenging applications, such as glycosylation monitoring of biological drugs and vitamin D analysis.

Two-dimensional liquid chromatography (2D-LC) allows much greater resolution of peaks than is possible in a classical single dimensional separation. For the next development in separations, we employed 2D-LC in two highly orthogonal dimensions of separation with four mass spectrometers for detection, with parallel detection in each dimension. We have further broken ground by using three dimensions of separation with four mass spectrometers, using two parallel second dimensions.

We present our annual review of new liquid chromatography columns and accessories, introduced between spring 2020 and spring 2021.

Dispersion of analyte peaks outside of chromatography columns can seriously erode the resolution provided by good columns. Here, we focus on the contribution of the sample injection step to the total level of extracolumn dispersion in an LC system.

Highlights of the new high-performance liquid chromatography, mass spectrometry, and chromatography data systems introduced over the past year.

We present our annual review of new products in gas chromatography, introduced between spring 2020 and spring 2021.

Dispersion of analyte zones outside of the column often compromises the quality of an LC separation—particularly in smaller columns with smaller particles. We explain basic concepts in extra-column dispersion from the point of view of an entire instrument.

Elmar Piel’s pioneering work was pivotal to the development of modern-day high performance liquid chromatography (HPLC).

Over the 17 years since the original Hydrophobic Subtraction Model for HPLC selectivity was published, those who curate the model have collected a huge amount of data as new HPLC stationary phases have been added. Analysis of this new data on almost 600 stationary phases has allowed us to update or adjust several of the stationary phase–analyte interaction terms within the model as well as adding one entirely new term to better describe the dipolar interactions with more modern stationary phases such as the pentafluoro phenyl-type phases.

Mycotoxins are toxic metabolites produced by fungal species often found in agricultural products. An accurate method for analyzing 12 regulated mycotoxins is described using UHPLC–MS/MS. The method demonstrated limits of quantitation (LOQs) for all analytes below stringent regulatory limits, making the method suitable for routine mycotoxin analysis.

LCGC Europe spoke to Stefan Van Leeuwen and Bjorn Berendsen from Wageningen Food Safety Research, The Netherlands, about a novel non-targeted approach to analyze PFASs using LC–HRMS with fragment ion flagging (FIF).

How do the characteristics of the mobile phase waves and retention properties of an analyte of interest impact retention precision?

Many of us have faced the situation where we have analytes that vary widely in their polarity or LogP(D) values and encounter issues with analyte solubility when choosing a suitable sample diluent for our high-pressure liquid chromatography (HPLC) analysis. The more polar analyte will favor aqueous solvents, and the less polar will be more highly soluble in organic solvent—so which do we choose?

This article reviews historical bonding techniques still in use for manufacturing high performance liquid chromatography (HPLC) stationary phases today, and also examines some emerging technologies that may be able to tackle unmet needs in novel platforms and phase construction.

Charged aerosol detection (CAD) is a powerful complement to ultraviolet (UV) absorbance and mass spectrometric (MS) detection for liquid chromatography (LC), particularly for analytes that have no UV chromophore, or do not ionize well by electrospray ionization. This article explores how to successfully use this technique.

The Dal Nogare award honors an awardee who is selected for contributions to the fundamental understanding of the chromatographic process. This year’s award winner is Professor Apryll Stalcup from Dublin City University.

This Friday morning session honors the 2021 LCGC award winners: Paul Haddad of the University of Tasmania, and the foundation director of the Australian Centre for Research on Separation Science (ACROSS); and Erik L. Regalado, of the pharmaceutical company Merck & Co.

Liquid chromatography (LC) pumps produce mobile-phase streams with short-term variations in mobile-phase composition. We explain the impact of these waves on retention time in reversed-phase LC and what to do about it.

A new free simulator is available for students, educators, and trainers to teach and perform virtual HPLC experiments that are applicable to real HPLC instrumentation and method development.

Even after 40 years, we have yet to find a perfect solution to the problem of demonstrating and achieving acceptable column precision for high-performance liquid chromatography (HPLC) packing material.

A UHPLC–MS/MS method is described for rapid quantification of five major bioactive alkaloids in rat urine. The results obtained help lay the foundation for the clinical application and safety evaluation of the bioactive ingredients of menispermi rhizoma, used in herbal medicines.