Getting Started in HPLC

Section 4. Using the Chromatogram to Get Results

This unit begins with the chromatogram we get after we have run a sample. At this point we have one or more peaks, which tells us something about how many compounds are present in the sample.

In the example at the right, we see three peaks, each corresponding to a different compound. So there are at least three compounds present in this sample. But what we usually want to know is what   compounds are present in the sample and how much  of each compound is present. The technique of "qualitative analysis" means finding out the identity of different compounds in the sample. "quantitative analysis" refers to measuring the concentration or amount of each compound in the sample.

Usually we want to carry out quantitative analysis on the sample, but this also means identifying the compounds whose concentrations we measure. In LC we use retention times to establish peak identity and band size (peak height or area) to measure concentration. In this example we have a report with the values of retention time, peak area, and peak height below the chromatogram.




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Last revised: April 06, 2001.