Chromatography Forum

Hi, all, I know that peak capacity can be calculated using PC=(T/Peak Width)+1 (T is the gradient time), but where is the "1" from? Thanks! xm

You see it immediately, if you think about it in the following way:

Take two peaks that are just separated. They will be separated by half the peak width of the first peak and half the peakwidth of the second, which is about one peak width for peaks eluting very close to each other. Thus the peak capacity is 2, since you are separating two peaks, which is the smallest peak capacity that you can define.

Got it, Many thanks, Uwe. -xm

This definition of the peak capacity seems to assume that the void volume of the column is a useful separation space. Is this correct?

No, it just assumes that the unretained peak is a peak too...