Liquid Chromatography (LC/HPLC)

In this month's column, John Dolan reveals a number of simple and useful shortcuts or rules of thumb that he has acquired over the years that allow quick estimates to guide method development or help solve a problem.

In this month's column the authors present a case study to outline several gradient quality checks that can be performed periodically to ensure proper performance of LC instrumentation. The example shows how by taking the time to perform such tests, potential problems can be identified before they reach a critical point.

In this article, the authors present a column ranking system to facilitate column selection in reversed-phase liquid chromatographic analysis. The system ranks columns based on their similarity to a reference column of choice and its applicability to a real pharmaceutical analysis is demonstrated.

Column Editor Ron Majors turns his attention to preparative chromatography. He focuses on the columns used in preparative chromatography, including how to select the appropriate mode, mobile-phase system and operating conditions.

Are you guilty of strange troubleshooting and maintenance habits that have been passed on to you from predecessors? John Dolan looks at some such practices, which were once acceptable, but don’t make sense in today’s lab.

In this article the authors review the use of elevated temperatures in HPLC, and provide examples covering separations of both small molecules and biomolecules. Generic issues of temperature dependence of retention and plate height are discussed, and comparisons are made between temperature gradient and solvent gradient elution. They describe how the use of elevated temperatures allow good chromatographic efficiency to be obtained at flow-rates higher than those optimal at ambient temperature, thus increasing the speed of separation.

The guest authors describe the use of LC–MS for the analysis of peptides. They deal with peptide extraction, peptidomic analysis in organisms with and without genomic databases, identification of peptides with conserved N- and C- terminal sequences, and in situ MALDI-TOF peptide profiling.

Maltodextrin is an easily digested carbohydrate made from corn starch...

VENTURE A affinity columns utilize ICEtechTM surface passivation technology...

Mini application note summaries...

Polymeric monolithic stationary phases offer an alternative to the classical microparticulate sorbents...

A report on the meeting that took place in April this year in York.

Column author, John Dolan, presents a simple but powerful isolation technique for identifying problems with LC methods and equipment.

The authors use the stochastic model to estimate the fundamental characteristics of the separation process.

A C18 stationary phase based upon a titanized silica support was prepared through reaction with octadecyltrimethoxysilane.

A look at the latest developments in preparative-scale columns, bulk packing materials, and column hardware designs.

The author focuses on a simple but powerful tool for isolating problems in the laboratory.

The separation of individual congeners of commonly used fluorescent whitening agents is described.

The authors study the solubility of five buffers commonly used in reversed-phase liquid chromatography.

In this month's column, John Dolan addresses some of the guidelines regarding system suitability tests and comments on their significance for those developing chromatographic methods.

A selection of mini application note write-ups

GC column bleed has been postulated to be caused by "backbiting" of the siloxane chain and volatility of noncrosslinked oligimers...

The authors discuss the application of shear-driven chromatography, a technique that depends on viscous drag to propel mobile phase in high-resolution/high-speed liquid chromatography. This method, it is claimed, overcomes the pressure- and voltage-drop limitations of both HPLC and CEC. Early development of the technique is reviewed and updated with the current status of the group's work. Also covered are the challenges faced and opportunities available to interface such systems to MS and UV/vis absorption detectors.