THE CHROMATOGRAM AND WHAT CONTRIBUTES TO IT

Characteristics of the chromatogram A properly operating system Reservoir 

Wide scope vs. high sensitivity Time constant The separation Capacity factor Selectivity Efficiency Resolution 

Molecular distribution between moving and stationary phases Normal and reverse phase Liquid-solid chromatography (LSC) 

When using the chromatogram for quantitative and/or qualitative analysis there are three important concerns. The first is that the LC system must be operating properly. Second, the HPLC must have appropriate detectors to see the compounds. Lastly, there must be a separation with appropriate spacing of the peaks so that the peak height (or the peak area) can be conveniently and accurately measured. This third issue implies that there must be retention of the compounds of interest. 

FIGURE 3-2. A typical isocratic HPLC. Plumbing considerations involve understanding the critical and noncritical bandspreading regions. 

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