Columns | The LCGC Blog

As I wrote the title of this month’s installment, I could not help but wonder where the cliché “more than one way to skin a cat” came from. Turns out it is from Mark Twain in his 1889 work, A Connecticut Yankee in King Arthur’s Court. I have never read that book, but I certainly have heard this saying used more than once-even if it might offend some cat lovers. Of course, it means simply that there is more than one way to do something.

Kevin A. Schug reveals the major method validation protocol deficiencies he discovered when he reviewed a blood alcohol investigation and discusses how matrix effects possibly resulted in blood alcohol concentrations being over-estimated, resulting in a potentially significant injustice.

I started my career working in a Quality Control laboratory. I'm familiar with the constraints that must be imposed to ensure consistent global standards and the pace at which change can be implemented without loss of control either within a business or across an industry. OK-scene set.

I am quite excited about some recent work we and others have performed related to fuels analysis using gas chromatography and vacuum ultraviolet spectroscopy (GC–VUV).

I’ve often written about the “lazy” chromatography which has swept through our industry, whereby 0.1% (w/w or w/v!) TFA or Formic acid is used to “buffer” the eluent system well away from the pKa of analyte molecules, leaving most acidic analytes in the ion suppressed form and most basic analytes in the ionized form. This approach avoids having issues with retention time drift and effectively eliminates pH as a variable used to control retention or selectivity for separations involving ionogenic analytes.

Kevin A. Schug discusses how matrix-assisted laser desorption–ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is one of the most versatile tools for fingerprinting mixtures.

In a recent review of blood alcohol casework performed by a forensics laboratory associated with a major metropolitan police force, I was again disheartened to find major deficiencies in method validation protocols. In this case, the analysts failed to check whether aqueous solutions for calibration and quality control were reliable surrogates for real blood samples.

I’ve done that thing where I’ve stated a very interesting title-I hope I can deliver something which lives up to it. I dislike it when people “overstate” their talk or poster titles at conferences to draw me in and then don’t deliver against the promise-I’ll let you judge how we go here.

Top-down protein quantitation, especially using triple-quadrupole MS, but even in general, has hardly been pursued. To help fill this gap, we recently reported a systematic investigation of intact-protein quantitation using multiple reaction monitoring (MRM) on a triple-quadrupole MS system, and we believe that this approach can be a promising alternative route to consider going forward.

Kevin A. Schug considers what the study of chemometrics and experimental design statistics can add to an analytical chemist’s work. Do analytical chemists lack an appreciation for the mathematical and statistical tools used to tease out important information?

The title of this piece may have put you off reading it – in which case you won’t be insulted when I say that even the most experienced gas chromatographers often fail to install columns in the best way possible.

Matrix-assisted laser desorption–ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is actually one of the most versatile tools for fingerprinting mixtures.

I believe that most analytical chemists do not appreciate what the world of chemometrics and experimental design statistics can add to their work.

Not every method is as we would hope it would be. Some methods come to us in imperfect form and we have to live with them, while others are difficult separations and, by necessity, need to be developed using close control of several variables such as eluent pH, eluotropic strength, ionic strength etc.

In 2009 I wrote an article on the emerging field “Bio Chromatography,” which for a small molecule analyst such as myself, perfectly described the situation. I realize that the separation of biomolecules had been happening for many years, but the expansion and development of protein based therapeutics from that point onwards has seen an avalanche of developments in instrumentation, sample preparation, and column technologies the like of which I have not seen in my 30 year career.

Compared to the magnitude of unconventional oil and gas development activity that has been performed by industry, the amount of research to assess its potential environmental impact has been miniscule. Can the process have a deleterious impact if not well managed? Can it be performed in a responsible manner?

I often get asked about the other important aspects of “screening” in HPLC, which include the mobile phase composition, gradient parameters and flow rate – so that’s the theme of this installment.

Here, I will attempt to convey a few basic but critical concepts when getting started in the development of a new LCxLC method.

I’ve been talking about ‘ToolKit’ method development platforms a lot lately and I have to say I’m not sure we are making the most of this approach.

What is required to produce a highly efficient modern high performance liquid chromatography (HPLC) system/column combination? This instalment of the LCGC Blog explains more.

The literature on reversed-phase liquid chromatography of proteins is reasonably well developed, but not taught in the college classroom to a significant degree. So I would like to focus on a stoichiometric displacement model for reversed-phase LC of proteins that I found to be particularly insightful from a practical standpoint.

If you don’t examine your LCMS data closely, you could be missing some of these effects, and those problems with your quantitative data will never be fixed.

Food analysis provides a rich sample matrix with many compounds of interest for analysis to contemplate-but one must always take care that the right tool is chosen for the desired task.

Some modern HPLC systems resemble spacecraft in terms of their technology, designed as they are to operate to the highest efficiencies, compared to traditional systems.

Column overload is a very commonly encountered issue in gas chromatography (GC) for beginners. Changes in peak symmetry, generally observed as peak fronting, can be subtle in the sharp peaks generated by GC, but the result can be significant shifts in retention times, loss of resolution, and error in peak integration. LCGC Blogger Kevin Schug explains more.

After 10 years at U.T. Arlington, I have decided it is time to take one of the best opportunities afforded to researchers in an academic faculty position-to travel abroad and assimilate new techniques into my repertoire to enhance future research activities.

There has been much written about the use of nitrogen as a carrier gas for capillary GC. Formerly, to say it wasn’t any good. Latterly to say that it’s pretty good and a better alternative to Helium than hydrogen from a practicality standpoint.

It is much more efficient to screen column chemistries to achieve optimum separations for a set of target analytes, than it is to play with different mobile-phase conditions on a single column. Kevin Schug explains more.

LCGC Blogger Tony Taylor offers some simple visual methods to assess column performance.

They say a picture paints a thousand words… This month I’ve taken inspiration from a recent webcast, presented at www.chromacademy.com, in which I presented real data from our work that represents some ‘classic’ GC problems.