Peak Shoulder

A peak shoulder (often simply referred to as a shoulder) occurs if a second substance with a (usually) considerably lower concentration is found below a large main peak. Peak shoulders normally do not have a distinct separate relative signal maximum of their own. Unlike peak shoulders, Rider Peaks usually have a distinct relative maximum of their own.

Chromeleon distinguishes between peak shoulders and rider peaks when defining retention time. As with main peaks, the peak retention time for rider peaks is defined as the time of the signal maximum. In contrast to this, the peak retention time for peak shoulders is the time with the maximum signal height over the baseline. Below the shoulder, the baseline is often inclined. That is why this time does not necessarily correspond to the time of the signal maximum.

Chromeleon usually skims peak shoulders in an exponential way: