chromatography terminology problem

Basic questions from students; resources for projects and reports.

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Could someone please explain what 'band', 'chart speed' and 'window' mean
in chromatography?

Thank you.

For the forum to help you more would you like to expand on your experience and background?

I appreciate that "band" in the context of band width or window will not mean a lot to any who are not familiar with the chromatography language. :-)

Chart speed refers to the days when the signal from the instrument was outputted to a chart recorder. ... 1471562294

A pen(filled with ink) responded to and recorded the varying output signal onto a moving roll of paper. The speed of the chart was usually 1cm/min. I really don't think that you need to worry about chart speed :-)



If you want to be pedantic about it, a "band" is the distribution of sample molecules running through the system. The "peak" is the response of the detector to those molecules when they come out of the column. Many people (myself included) use the terms interchangeably.

In chromatography, an analyte is identified by its retention time (the time it takes to get through the column. The "window" (as part of a chromatographic method) generally refers to uncertainty in that retention time. For example, in a (hypothetical) method for dimethylchickenwire (DMCW) and trimethylchickenwire (TMCW), if a pure standard of DMCW has a retention time of 2.6 minutes and TMCW has a retention time of 3.5 minutes, then the method might be set up so that any peak with a retention time in the window of 2.4 - 2.8 minutes is identified as DMCW, and any peak with a retention time in the window of 3.3 - 3.8 minutes is identified as TMCW. The width of the window would chosen based on the variability in the retention times.
-- Tom Jupille
LC Resources / Separation Science Associates
+ 1 (925) 297-5374
Ralph: thank you for your explanations :-) I have just started to study chromatography and have not much experience in using GC and HPLC..the terminologies used in chromatography are sometimes confusing which led me to join this forum to learn more :-)

tom jupille: thank you for detailed explanations of 'window' - it is now clear what it means :-)
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