Columns | Column: Column Watch

In recent years industry has been moving to columns with smaller and smaller inner diameters-moving from 4.6 and 3.0 mm i.d. columns to 2.1 mm, 1.0 mm, and even smaller. While small inner diameter columns have some clear advantages, they also bring challenges. Reduction of extracolumn volumes must be given greater consideration by both customers and manufacturers. Additionally, experimental evidence suggests that the very narrow confinement of chromatographic particles can result in packed bed structures that promote increased dispersion and reduced efficiency. This article focuses on the sources of band broadening within high performance liquid chromatography (HPLC) columns with particular emphasis on eddy dispersion. The physical mechanisms of dispersion are discussed and a review of the current literature as it pertains to small inner diameter columns is presented.

Our annual review of new LC columns and accessories introduced at Pittcon and through the previous year.

In his final “Column Watch” article, Ron Majors looks into his crystal ball and discusses future needs in the area of HPLC/UHPLC column technology and related instrumentation. He looks at where current technology may be heading and makes a prediction that monolith-based columns may still have a rightful place in the HPLC/UHPLC laboratory .This article concludes his duration as a monthly columnist for LCGC.

During the course of my scientific career beginning in the 1960s, I have grown up with the birth of modern LC column technology, the refinements of the instrumentation, and the development of widespread application of this most powerful separation and analysis technique. In this installment, I would like to share with you some of my observations and experiences with the beginning, the growth period, and the maturation of HPLC columns, where I have focused nearly 33 years of writing for this magazine. I will explore some of the early column breakthroughs beginning with the development of large superficially porous particles (SPP), the porous irregular and spherical microparticulate particles, inorganic and organic polymeric monoliths and the rebirth of the current generation of SPP. In next month’s installment I will look into my crystal ball and see what the future of HPLC and UHPLC holds.

HPLC 2015, chaired by Gérard Hopfgartner was held in Geneva, Switzerland, from June 21–25. This installment covers some of the highlights observed at the symposium including stationary phase developments, particle technology, and areas of growing application of HPLC. In addition, trends and perspectives on future developments in HPLC culled from the conference are presented.

The use of superficially porous particles in the manufacture of high performance liquid chromatography (HPLC) columns has become prominent in recent years. Over the course of the past decade most major manufacturers have built column lines around the technology.

 Volume 33 Number 4Pages 234-247This is our annual review of new liquid chromatography (LC) columns and accessories introduced at Pittcon and throughout the previous year. This year, Michael Swartz, former author of our "Innovations in HPLC" and "Validation Viewpoint" columns, steps in as a guest columnist to write the review.

 There has been a revival of supercritical fluid chromatography (SFC) in recent years, especially in the chiral preparative field, but also more recently in the analytical area. However, SFC is considerably more complex than liquid chromatography (LC), mainly because of the compressibility of the mobile phase. One can say that SFC is a "rubber variant" of LC where everything considered constant in LC varies in SFC. In this review, we go through advances in theory, instrumentation, and novel applications.

Understanding the interactions that stationary-phase chemistries provide will help you choose the most appropriate blend of interactions to address a given separation challenge.

To obtain the best performance from your UHPLC system, you need the right tubing and fittings. Here is what you need to know.

Understanding the chemistry of embedded polar group and perfluorophenyl phases leads to better decisions during method developement

Mechanical strength, acid and alkaline durability, loadability, and overload characteristics are a few of the parameters evaluated.

Highlights of the discussions on column-technology topics - such as monoliths, high-pH columns, SPPs, and HILIC - and an analysis of the larger trends observed at the conference.

New GC columns, SFC columns, and products for sample preparation, including small benchtop instruments

New product introductions in the areas of HPLC columns for reversed-phase LC, HILIC, ion-exchange and ion chromatography, SEC, and specialty columns for specific types of analyses are covered.

Stacking and sweeping injection methods are compared and practical suggestions are provided about how to enhance sensitivity for charged and neutral compounds.

Highlights of the column technology observed at the symposium

A review of the advances and trends in technology and applications discussed at the HPLC 2013 conference, including a summary of the awards presented.

A summary of the results from a survey of 14 leading HPLC–UHPLC column experts is presented, covering the state of sub-2-?m porous particles, superficially porous (core–shell) particles, silica monoliths, and polymeric monoliths.

Evidence to demystify HPLC and UHPLC column myths

For the next improvements, we must look beyond the column.

This month's installment of "Column Watch" comprises Part II of our yearly report on new products introduced at Pittcon. Gas chromatography columns, sample preparation products, and hardware, accessories, and small tabletop instruments mainly for sample preparation are covered.

Part I of our yearly report, covering columns for all modes of HPLC, UHPLC, and liquid-phase separations.

A look at what influences the use of CE in the pharma industry.

Professor Mary Wirth and graduate students Bingchuan Wei and Benjamin Rogers from Purdue University demonstrate a quantum leap in protein column efficiency. Using colloidal silica particles of submicrometer diameters (470 nm), they obtained plate heights that were as much as 15-fold lower than the theoretical limit for Hagen-Poiseuille flow.

A review of the trends at this year&s symposium, including discussions of column technology, sample preparation, and detector usage.

A comprehensive review of standard and specialty SEC columns, including up-to-date charts and advice on how to choose

Advantages of the planar, off-line format of TLC relative to on-line column HPLC, the steps in TLC analyses, and future prospects of TLC are discussed.

What you need to know about gas chromatography columns, thin-layer chromatography plates, sample preparation products, as well as chromatography and sample preparation accessories (including small benchtop instruments) unveiled at Pittcon this year