The LCGC Blog

Oct 05, 2017
Data validity and a thorough understanding of the results that we produce should be of great interest to us all. Here's why.
Sep 27, 2017
Internal standards (IS) are commonly incorporated into quantitative methods to increase accuracy and precision. An IS is a compound that is different than the analyte of interest, has similar physicochemical properties to the analyte, and is added to samples, calibration standards, and quality control samples in a known quantity. It should not be present in the sample, it should be available in high purity, and it should be easily differentiable from the analyte of interest.
Sep 12, 2017
With the increasing proliferation of UHPLC, with its very much reduced extra column volumes, is the concept of dwell volume still relevant? Indeed, in your world, was it ever relevant at all?
Aug 29, 2017
As the fall semester starts, I begin my 13th year as a chemistry professor. Let me get right to the point—if you do not love this job, you will hate it!
Aug 07, 2017
The ability to rapidly screen stationary phases through column-switching capabilities provides significantly greater efficiency in method development than was previously possible. The approach does require some additional hardware and software. And, while such capabilities may limit the ability to expand one’s literary knowledge during excessive months in the laboratory developing separation methods, real progress to key decision points for method optimization can be realized instead.
Jul 26, 2017
Until recently, I hadn’t heard of ternary or quaternary gradients being used for many years. They have gained a reputation for being somewhat difficult to reproduce—less robust, if you like.
Jul 10, 2017
The LCGC Blog
Hydrophilic Interaction Chromatography can be a very useful tool in our analytical armory, however there are some practical peculiarities to this chromatographic mode which need to be understood in order to ensure success. 
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.
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