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Gas Chromatography with Vacuum Ultraviolet Absorption Detection

LCGC Blogger Tony Taylor provides his impartial guide to liner selection that is representative of the considerations in modern capillary gas chromatography (GC).

When a scientist needs to search through scientific literature, which is the preferred search engine? While there is quite a bit of variety in available search engines, LCGC Blogger Kevin Schug has a definite preference. Here's what it is, and why.

When you begin to now combine advances in superficially porous media to achieve high efficiency with novel and predictable new stationary phases to achieve high selectivity, then it sounds like the evolution of HPLC and UHPLC phases over the past decade or more has brought some exciting new possibilities.

Is 0.1% TFA (aq) / 0.1% TFA in acetonitrile the ultimate robust HPLC mobile phase? Maybe not...

Much has been written about column overload, however, I've seen many instances lately in which overload may not be instantly recognized, or causes problems that may not normally be attributed to overload. Therefore, I wanted to explain how to spot and deal with different types of overload situations.

If you ask scientists, it does not take long before you realize that there is quite a bit of variety in the different search engines that they prefer.

The International Symposium on Capillary Chromatography (ISCC) and GCxGC Symposium combined conference provides an excellent combination of high impact, cutting edge science, and a great social program in an interesting venue. Kevin Schug shares his thoughts about innovations in gas chromatography presented at this year's conference in Riva del Garda, Italy.

When developing a separation, some fundamental choices need to be made on how we might achieve the separation we require - primarily the mode of chromatography used and the way in which we intend to control and optimise the retention and separation (selectivity) of analyte components.

Many troubleshooting investigations in chromatography often don?t lead to a single causal factor. Often, the reason for problems or lack of method robustness are related to many small ?contributory factors? and this is particularly true of the problems associated with sample introduction in capillary Gas Chromatography.

Solid-phase extraction (SPE) is a versatile and reliable technique that is often used for sample cleanup and concentration. Kevin Schug offers some insight about SPE basics and achieving successful extractions.

This blog attempts to provide an impartial guide to liner selection which is representative of the considerations in modern capillary GC.

Graduate students seeking doctoral degrees in chemistry require guidance and help in completing their dissertations. In the April installment of The LCGC Blog, Kevin Schug discusses this process and the efforts of four of his students.

Of late we have been running a series called 'Lock and Leave', which serves as a reminder to pay attention to those instrument parameters which are often overlooked - you know the type of thing ? 'that's the best value for this system?, 'we always set to that value' and 'I have no idea what that does' ? it's always at that value'.

The United States woefully underfunds international collaborations with the Czech Republic. Yet, it is a country that produces excellent scientists who are distinctly passionate about science, and who have been educated to demonstrate not only a strong mastery of chemistry basics, but also superb knowledge of the integration of high-level mathematics and computer programming skills into their science. One need not look very far in the separation science and mass spectrometry (MS) fields in the United States to find eminent leaders with roots in the Czech Republic.

Surrogates, Internal Standards, Isotopically labelled Standards, External Standards, Calibrants, QC Samples etc. etc. - our working lives are littered with checks to ensure that our instruments are giving us the correct results. And rightly so. But do we always use these checks correctly? Do we know what we are checking and why? Indeed, do we know how to design methods/procedures which employ a valid checking regime, often referred to as a Quality System? Let's find out.

Analytical chemists entering the work force are not always ready to face the challenges of private industry. Kevin Schug discusses how best to prepare students for the next stage of their careers.

An assembly of thoughts on all things filtration for HPLC - and how to deal with various nasties - from Rocks to Sand.

There has been much focus within the industry of late on ways of improving the way in which HPLC method development is carried out - which has led to a more widespread adoption of modelling and optimisation software combined with dedicated method development platforms from the major instrument vendors.

Flow injection analysis (FIA) is a powerful technique for quantitative analysis, especially in conjunction with mass spectrometry (MS) detection. Kevin Schug discusses how FIA can be combined with MS using electrospray ionization and describes how the technique can be used for analytes such as binding constant determination, multipoint instrument response calibrations, and removing the dependence of measured analyze concentrations on matrix effects.

No, this isn't a new detective novel, in fact its two concepts which were "coined" by my good friend John Hinshaw during a recent CHROMacademy webcast which we presented together on sample introduction for capillary GC.

Choosing the correct column for an application really requires that we consider the many factors which can influence the efficiency and selectivity of a separation including column hardware, support and surface chemistry. On a rainy day a little while ago our technical support group came up with a list of 23 such factors which need to be considered.

What would you do if faced with a zombie invasion in your analytical laboratory? LCGC Blog editor Kevin Schug provides guidelines and suggestions for fending off an attack, including how to use glassware and dead chromatography columns as defensive weapons and novel applications for laboratory lasers.

Tony Taylor provides insight on the best way to choose GC columns based on analyte or sample characteristics.

Researchers coupling high performance liquid chromatography to mass spectrometry face the challenge of segregating the ionized, typically nonvolatile analytes from a large amount of solvent, and the mobile phase is an important component in the process. LCGC Blog editor Kevin Schug discusses factors to consider when choosing a mobile phase for LC-MS.

Chromatography can be approximated by a series of equilibrium events between the mobile phase and stationary phase. Here, LCGC Blog editor Kevin Schug discusses an exceptional spreadsheet macro written by an undergraduate researcher that helps users visualize the development of chromatographic separations.

Chromatography can be approximated by a series of equilibrium events between the mobile phase and stationary phase. Here, LCGC Blog editor Kevin Schug discusses an exceptional spreadsheet macro written by an undergraduate researcher that helps users visualize the development of chromatographic separations.

Split/splitless injectors typically vaporise a sample dissolved in a suitable organic solvent under increased temperature. The sample vapours are entrained into the carrier gas flow inside a "liner" or "sleeve" within the inlet and from there pass into the column or out of the inlet via "split" line / valve. Splitless injection is used to perform an "on-instrument" dilution and the relative amounts of sample which enter the column or discarded to waste via the split line are adjusted using the relative carrier and split flow rate ratio.

J. Calvin Giddings provided one of the most practical discussions of the advantages of temperature programming in GC over isothermal analysis back in 1962. Here, Kevin Schug describes some of the salient points of that discussion and how they still apply today.

This month we take a look at the important topic of buffer choice for HPLC separations, how to the choose the correct buffer type and concentration as well as how to avoid variability in retention and selectivity.