Jun 28, 2017
I believe that the term “top-down proteomics” holds a particular connotation with respect to the use of ultrahigh-resolution mass spectrometers in people’s minds. And rightfully so. If one is to determine with confidence the sequence and charge state of a particular fragment ion generated in the gas phase, then high mass accuracy is a must. From the discovery side of things, where qualitative analysis is most important, this is not likely to change. However, when you turn to quantitative analysis, where you want to now monitor levels of a particular protein biomarker for the purpose of disease diagnosis, prognosis, or treatment, then invariably bottom-up strategies are the norm. Protein quantitation using top-down strategies, especially on low-resolution triple-quadrupole systems, have been largely ignored, until recently.
Jun 02, 2017
I’m often asked “what reproducibility should I expect to get from my [insert instrument manufacturer and model]?” So, most folks are referring to the repeatability aspects of precision, as in: “what relative standard deviation (usually expressed at %RSD) for peak area or quantitative result should I be able to achieve from repeat injections from a single vial of sample?”
Jun 01, 2017
Precise and accurate quantitative analysis based on chromatographic measurements has historically relied very heavily on careful peak integration. Seasoned analysts know that while automated algorithms exist in modern chromatography software, it is a best practice to manually check that the integration points—the points at the beginning and end of a peak, between which the peak will be integrated to obtain a peak area—are appropriately specified.
May 05, 2017
The LCGC Blog
I guess we have all had the issue at some time or other. A blank injection of eluent (or a zero volume dummy injection) gives rise to discrete peaks on the chromatographic baseline that may interfere with analyte peaks or increase the complexity of the chromatogram obtained, especially when performing trace analysis. Of course this is an undesirable situation and one that can be difficult to understand or troubleshoot as, if we didn’t inject anything, how on earth do we end up with discrete peaks in the “blank” chromatogram? The secret to understanding the phenomenon lies in understanding the mechanisms of gradient HPLC.
May 03, 2017
The LCGC Blog
As part of the Earth Day celebration in Dallas, Texas, last month, the Collaborative Laboratories for Environmental Analysis and Remediation (CLEAR) at U.T. Arlington hosted the first annual Responsible Shale Energy Extraction (RSEE) symposium ( We had an exceptional range of speakers who conveyed all sides of the issue, including U.S. Secretary of Energy Rick Perry and atmospheric scientist Dr. Katherine Hayhoe from Texas Tech University, one of Time’s top 100 most influential people. We had representatives from major oil producers, environmental groups, land management groups, water recycling service companies, and scientists conversant on many key issues related to unconventional oil and gas (UOG) extraction. Even though we have been very involved in this conversation for the past several years, several points stood out.
Apr 04, 2017
As I’ve written previously, our Nirvana in HPLC column selection would be to enter the structures of our analytes and have a database tell us the column and mobile phase conditions that we should use to carry out the separation successfully. Although I know of several groups who are working on this, in practice we are still a long way from realizing this goal.
Mar 31, 2017
I have written previously about occupying the middle ground in the debate over the environmental implications of unconventional oil and gas extraction operations. It seems we are just in the right place, when we are criticized and praised at separate times by proponents of both extreme views—namely those who think UOG is perfectly safe and those who think it cannot be done without ruining the environment.
Mar 01, 2017
A short treatment of what to consider when choosing the appropriate sample solvent so you can be better informed when developing, optimizing, transferring, or troubleshooting your GC methods.
Feb 27, 2017
Students who have an internship on their resume, and are seeking jobs in a particular sector, are doing so with an informed opinion. While an internship comes in many forms, that real-world experience has provided a clear touchstone of understanding of what it would be like to work in a given sector.
Feb 06, 2017
This time I’m going to be looking at how to get the most from your GC–MS (Gas Chromatography–Mass Spectrometry) system, and I intend to keep things as simple as possible, however I also make no apology in the fact that some of the concepts may be beyond your current understanding. My intention here is to explain some of the basics so that you will be able to use your instrumentation to best effect.
lorem ipsum