Liquid Chromatography (LC/HPLC)

Errors arising from the DNPH approach commonly used to analyze carbonyl compounds in smoke from heat-not-burn (HNB) tobacco can be avoided by using the approach described in this study.

Are we ready to let software and instruments take over the art of separations?

Here, a new automated active pharmaceutical ingredient (API) extraction platform is integrated with online liquid chromatography (LC) to assess drug product potency. The platform dissolves the tablet coating (if present), disintegrates the tablet, and disperses and solubilizes the tablet for analysis.

Deviations from the expected pressure in modern LC systems (too low, too high, or fluctuating) can be diagnosed and more quickly resolved using the streamlined troubleshooting practices shown here.

In this month’s blog, we provide information about the Subdivision on Chromatography and Separations Chemistry (SCSC) of the Analytical Division of the American Chemical Society (ACS), sharing our main goals and introducing our newly appointed executive board members.

An improved LC–MS/MS method that can rapidly detect fipronil, an insecticide harmful to human health, is presented here for chicken eggs, feed, and soil.

With modern chromatography modeling software, is it time to hang up our laboratory coats? Is resistance to software solving separations futile?

The UHPLC–MS/MS method can accurately determine the presence of these illegal feed additives in swine tissues.

Improved analysis of pharmaceutical and natural medicine products requires advances in reversed-phase LC stationary phases. We examine two synthesized stationary phases with applicability in quality control and chiral separation for analysis of natural products.

GC and TLC methods are demonstrated for quantification of stigmasterol 3-O-β-D-glucopyranoside (S3G), the main active component in the herbal nutraceutical Balanites aegyptiaca, an antihyperglycemic in Egyptian folk medicine.

This article discusses the development of a series of applications that will allow for the determination of a number of nitrosamines that have been identified by the FDA as genotoxins to monitor, initially showing how to perform a separation of these compounds from the API and then looking at how MS can be applied to the analysis to ensure that the required detection limits can be reached.

In recent articles, the authors 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.

Recent developments in open-tubular liquid chromatography (OTLC) are explored with an emphasis on advances in column technology.

The more polar analyte will favour aqueous solvents, and the less polar will be more highly soluble in organic solvent—so which do we choose?

Ensuring complete overlapping (coelution) of analyte and internal standard peaks can be critical for eliminating matrix effects in LC–MS/MS analysis.

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

Reducing the column inner diameter results in a reduction in chromatographic dilution and increased sensitivity, allowing for more efficient tandem mass spectrometry sampling (MS/MS) and a higher number of molecule identifications.

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.

The effects of water on retention and selectivity in gas–solid chromatography of various adsorbent PLOT columns is reviewed.

Our annual review of new liquid chromatography columns and accessories, introduced at Pittcon and other events over the past 12 months.

This instalment focuses on basic concepts in extracolumn dispersion (ECD) that occurs in high performance liquid chromatography (HPLC) systems, and the impact of this dispersion on the performance of columns of different dimensions and efficiencies.

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.

The talks in this session highlight developments in liquid chromatography (LC), including a computer-assisted modeling approach to simplify 2D-LC method development, the use of aligned continuous gradient stationary phases, the development of alkaline-stable packing materials based on calcium carbonate, and more.

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.

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.