HPLC

What’s not in your standard operating procedure? Documenting details can prevent headaches associated with method transfers between laboratories.

What are the potential problems that may be encountered using UHPLC systems and methods, and what strategies can be used for their mitigation?

John shares lessons learned from his more than three decades of teaching liquid chromatography practitioners and helping them solve their problems.

In this extended special feature to celebrate the 30th anniversary edition of LCGC Europe, leading figures from the separation science community explore contemporary trends in separation science and identify possible future developments. We asked key opinion leaders in the field to discuss the current state of the art in liquid chromatography column technology, gas chromatography, sample preparation, and liquid chromatography instruments. They also describe the latest practical developments in supercritical fluid chromatography, 3D printing, capillary electrophoresis, data handling, comprehensive two‑dimensional liquid chromatography, and multidimensional gas chromatography.

In this extended special feature to celebrate the 30th anniversary edition of LCGC Europe, leading figures from the separation science community explore contemporary trends in separation science and identify possible future developments. We asked key opinion leaders in the field to discuss the current state of the art in liquid chromatography instruments.

The last decade has witnessed how liquid chromatography columns and instruments changed from long bulky columns with relatively large fully porous particles operated at modest pressures (100–200 bar), to short compact columns with small superficially porous particles operated at ultrahigh pressures (1200–1500 bar). This (r)evolution has resulted in a tremendous increase in achievable separation performance or decrease in analysis time, but requires a good knowledge of optimal chromatographic conditions for each separation problem and, concomitant, the right instrument configuration.

In his final column before retirement, John Dolan reflects on the changes he has seen during his 34 years as the author of “LC Troubleshooting,” and shares his short list of best practices that still hold true today.

Liquid Chromatography and High-Resolution Mass Spectrometry In food analysis, HPLC and triple-quadrupole mass spectrometry are established techniques. Jon Wong of the Center for Food Safety and Applied Nutrition at the U.S. Food and Drug Administration discusses why his agency and others have been developing food analysis methods using UHPLC and HRMS.

Dwight Stoll, who will take the reins of “LC Troubleshooting” next month, spoke with John Dolan to get some insight on the current state of chromatography with John Dolan to get some insight on the current state of chromatography training, future troubleshooting problems, John’s toughest troubleshooting challenge, and the most common chromatographic mistakes.

This instalment on ultrahigh-pressure liquid chromatography (UHPLC) reviews the potential problems that may be encountered using UHPLC systems and methods, and proposes strategies for their mitigation.

How do non-alkylsilica columns provide us an additional dimension of column selectivity?

This instalment in our series on ultrahigh-pressure liquid chromatography (UHPLC) highlights its benefits in fast analysis, high-resolution separations, high performance liquid chromatography (HPLC) method development, reduced solvent and sample usage, and enhanced sensitivity and precision performance.

We consider some of the details associated with preparing a column for storage, with an eye toward choices that will pay dividends in future use.

Several factors influence the useful lifetime of high performance liquid chromatography (HPLC) columns. In this instalment we consider some of the details associated with preparing a column for storage, with an eye towards choices that will pay dividends in future use of the column.

Buffers are commonly used in reversed-phase liquid chromatography (LC) to control the ionization state of analytes. However, the addition of buffers is much more complex than simple pH control. Complex equilibria exist between these mobile-phase additives, the analytes, the silica surface, and even the stationary phase in certain circumstances. The addition of mass spectrometry (MS) as a primary detection technique makes decisions about mobile-phase additives even more crucial. In this column instalment, we use a model set of analytes and selected applications to demonstrate the effects that buffers can have not only on the selectivity of a separation, but also on the sensitivity of a reversed-phase analysis when using MS detection.

Some 50 years after Giddings’s iconic comparison of the separation speed of gas chromatography (GC) and liquid chromatography (LC), the authors revisit this comparison using kinetic plots of the current state‑of‑the-art systems in LC, supercritical fluid chromatography (SFC), and GC. It is found that, despite the major progress LC has made in the past decade (sub-2-µm particles, pressures up to 1500 bar, core–shell particles), a fully optimized ultrahigh-pressure liquid chromatography (UHPLC) separation is still at least one order of magnitude slower than capillary GC. The speed limits of packed bed SFC are situated in between.

This instalment highlights historical perspectives on the development of ultrahigh-pressure liquid chromatography (UHPLC) into a modern high performance liquid chromatography (HPLC) platform and describes the important instrumental features common to most commercial equipment.

The HPLC symposium series is recognized as “the forum” where new developments in liquid phase separations and their hyphenation to mass spectrometry (MS) for the analysis of (bio)pharmaceutical compounds and their metabolites are presented.

This instalment highlights new high performance liquid chromatography (HPLC) systems, modules, and software that were introduced at Pittcon 2017 and during the year prior, and describes their innovative features and significant benefits.

Peter Myers from the University of Liverpool (Liverpool, UK) spoke to David McCalley from the University of the West of England (Bristol, UK) about the past, present, and future of stationary phases, and his working life in academia and industry.

This article describes a space-saving, quick, and inexpensive sample preparation technique followed by a high performance liquid chromatography (HPLC) method with a 100% water mobile phase and photodiode array (PDA) detection for quantifying acetamiprid and its N-desmethyl metabolite, IM-2-1, in cow’s milk. The analytes were extracted from the sample and deproteinized using a handheld ultrasonic homogenizer with 5% (w/v) trichloroacetic acid solution, purified using a centrifugal monolithic silica spin minicolumn, and quantified within 20 min per sample. The accuracy and precision are well within the international method acceptance criteria.

The free spreadsheet-based program HPLC Teaching Assistant was developed for effective and innovative learning and teaching of liquid chromatography. This software allows teachers to illustrate the basic principles of high performance liquid chromatography (HPLC) using virtual chromatograms (simulated chromatograms) obtained under various analytical conditions. In the first instalment of this series, we demonstrate the possibilities offered by this spreadsheet to illustrate the concept of chromatographic resolution, including the impact of retention, selectivity, and efficiency; understand the plate height (van Deemter) equation and kinetic performance in HPLC; recognize the importance of analyte lipophilicity (log P) on retention and selectivity in reversed-phase HPLC mode; and manipulate or adapt reversed-phase HPLC retention, taking into account the acido-basic properties (pKa) of compounds and the mobile-phase pH.

The 45th International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 2017) will be held from 18 to 22 June 2017 at the Prague Congress Centre, Prague, Czech Republic.

The mobile phase pH can be a powerful tool to control retention and selectivity, but it can also get you in trouble if not controlled properly.

Part II of this series describes additional features of the HPLC Teaching Assistant software, including the possibility to simulate the impact of the mobile phase temperature on HPLC separations; understand the chromatographic behavior of a mixture of diverse compounds in both isocratic and gradient elution modes; show the influence of instrumentation (injected volume and tubing geometry) on the kinetic performance and sensitivity in HPLC; and demonstrate the impact of analyte molecular weight on thermodynamic (retention and selectivity) and kinetic (efficiency) performance.

This article describes a workflow for the analysis of phenolic components in wine enabling confident differential analysis using high performance liquid chromatography (HPLC) in combination with low-field drift-tube ion mobility quadrupole time-of-flight mass spectrometry (IMS-QTOF-MS).

This free software allows teachers to illustrate the basic principles of HPLC, such as chromatographic resolution, the van Deemter equation, and how to manipulate or adapt retention in reversed-phase HPLC.

HPLC 2016, chaired by Professor Robert Kennedy, was held June 19–24 in San Francisco, California, at the Marriott San Francisco Marquis. This installment of "Column Watch" 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 noted from the conference are presented.

Detectors based on ultraviolet absorbance are the most common detectors in use for liquid chromatography.

There can be significant benefits by standardizing HPLC columns in a pharmaceutical development laboratory. Here is a story of how one organization attempted to encourage its staff to develop HPLC methods using fewer column brands and dimensions to reduce waste and efforts in method transfers downstream.