HPLC and GC Articles

If you are a regular reader of "LC Troubleshooting", you will know that I am a strong proponent of using an in-line filter to protect the LC column. The filter contains a frit, most commonly 0.5 µm in porosity, and is mounted directly downstream from the autosampler.

This installment of Validation Viewpoint describes how statistically rigorous quality-by-design (QbD) principles can be put into practice to accelerate each phase of liquid chromatography (LC) instrument method development. Here, in Part I, the authors examine the current approaches to column screening in terms of design space coverage — a key element of process knowledge.

Part III concludes the print version of our three-part series, "A Mass Spectrometry Primer," with the glossary to follow in a fourth and final installment. To recap the basis for undertaking this work, technological changes that affect our knowledge, in terms of its depth and our speed of accessing it, spur a couple of observations about print media versus electronic.

Here we are, more than 40 years after the initial exploration of high performance liquid chromatography (HPLC). Many things have changed, some innovations have come and gone, but the reciprocating-piston pump still remains as a key component of the LC system.

Recently, I had the opportunity to participate in Colacro XII, a chromatography symposium held in a Latin America country every two years. This year's meeting was held in Florianopolous, Brazil, October 27-30. During the symposium, I perused the large number of applications posters for the sample preparation techniques being used.

Regulations typically move at a snail's pace as we're dealing with governments: slow to be generated, slow to be enacted and slow to be changed. But just like waiting for a bus, you wait for ages and then several come along at once!

Microemulsions are stable, isotropically clear solutions consisting of an oil (such as octane) and water stabilized by a surfactant and co-surfactant. To form such a mixture the interfacial tension between the oil and water has to be decreased by the addition of both a surfactant and a co-surfactant.

The launch of porous sub-2 μm particle stationary phases, combined with the simultaneous commercialization of compatible chromatographic instruments for these column geometries,1,2 has increased the amount of liquid chromatography (LC) development, particularly in the field of high-throughput separations.

For most of the past 40 or so years that pressure-driven liquid chromatography (LC) has been used, problems related to air bubbles in the pump and detector have been at the top of the list of LC-related problems. The regular use of helium sparging or vacuum degassing reduced these problems to an acceptable level in many laboratories.

Natural products have served mankind as a source of medicine since — and even before — historical records began. Herbal extracts now play an important and growing role in disease prevention and therapy, and are used extensively as drugs and food additives.