Liquid Chromatography (LC/HPLC)

Tips & Tricks GPC/SEC: Answering Common Questions About GPC/SEC Columns

Where Can I Draw The Line?

This installment provides an overview of modern practices of high-throughput purification to support small-molecule drug discovery.

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.

Readers' questions regarding problems related to internal standard calibration of liquid chromatography methods are addressed.

This work presents an on-line combination of a simple microgradient device for reversed-phase liquid chromatography (LC) and electrospray ionization (ESI) tandem mass spectrometry (MS-MS).

Changes to the European Food Safety Authority (EFSA) regulations on food labelling, and the strengths and limitations of new and existing methods for the detection of allergens in food are discussed in this article.

Beer is one of the most popular drinks in the world. Based on natural products, quality control to guarantee a product of consistent taste, colour, and composition can be challenging. Amino acids analysis can be used to ensure consistency in the quality of the end-product, and also as an indicator for counterfeiting of branded products. In this article we present a rapid and reliable high performance liquid chromatography–mass spectrometry (HPLC–MS) method to determine amino acids in beer.

When converting methods from liquid chromatography (LC) to ultrahigh-pressure liquid chromatography (UHPLC), don't get confused by flow-rate settings.

This installment highlights noteworthy high performance liquid chromatography (HPLC) and related products introduced at Pittcon 2015 in New Orleans, Louisiana, as well as in the year prior.

 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.

The statistical overlap theory (SOT) of chromatography relates the number of peaks that appear in a chromatogram to the number of detectable components and the peak capacity.

A liquid chromatography–electrospray ionization tandem mass spectrometry (LC–ESI-MS-MS) method has been developed to determine multiple preservatives in cosmetics and personal care products.

Enhanced-fluidity liquids are organic solvents or organic–aqueous solvents mixed with high proportions of liquefied gases, such as carbon dioxide.

The most significant recent advancement in liquid chromatography (LC) column technology is the new generation of superficially porous silica particles.

Internal standard methods are used to improve the precision and accuracy of results where volume errors are difficult to predict and control.

One of the most frequent times that we discover a problem with a liquid chromatography (LC) method is when we examine a data set following the analysis of a batch of samples.

 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.

Limonin was separated from other components in citrus juice sample matrices by reversed-phase chromatography with ultraviolet detection.

There is a bewildering array of stationary-phase choices available for reversed-phase high performance liquid chromatography (HPLC), and even within each phase designation (such as "C18") the selectivity of each phase can vary widely.

Despite the utility of high performance liquid chromatography (HPLC) simulators, we found that all the free and low-cost simulators were outdated or had extremely limited functionality, so we created one that addressed these shortcomings. We developed a sophisticated, open-source HPLC simulator that is available for free as well as a version for Android users called "HPLC Simulator." Here we discuss a few questions that the simulator can help answer: Why are peaks narrower in gradient elution? What is gradient delay and how does it affect a separation?

Marijuana, the common or slang term for cannabis in its herbal form, is one of the most widely used illicit drugs in the world.

Why are liquid chromatography retention times sometimes so slow to stabilize?

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

Methotrexate and sulfasalazine are often used together to treat rheumatoid arthritis, so it is valuable to be able to monitor plasma levels of both drugs simultaneously. This method achieves that by using two detector wavelengths, 304 nm for methotrexate and 358 nm for sulfasalazine.