Example: retention time updates with RRT

If you automatically update the retention times, and also use relative retention times, the values are updated as follows:

• The expected RT of the RRT reference compound is calculated as shown in the equation for NewExpRT (see Calculations for updating retention times)

• The expected RT of the associated compound is adjusted to keep the RRT values constant, as shown in the equation for Expected RT_compound (see Calculations for relative retention times (RRT))

• The RT start and RT stop times of a timed group are adjusted to keep the RRT values constant, using the same equation as for the expected RT_compound.

For example, consider a processing method with 3 compounds and a Timed Group, where RT Update and RRT are used:

 

Compound parameters

 

Timed group parameters

After processing an injection, the 3 compounds were found at the following retention times:

• RRT ref: 4.000 min

• C2: 8.000 min

• C3: 2.000 min

As a result, the expected RT of the RRT reference compound is corrected as follows:

The expected retention times of the other compounds as well as the start and stop times of the timed group are adjusted, so that RRT is constant.

Expected RT_compound = RRT * expected RT_reference

Expected RT_C2 = 2.000 * 3.500 min = 7.000 min

Expected RT_C3 = 0.500 * 3.500 min = 1.750 min

RTStart_TimedG = 1.000 * 3.500 min = 3.500 min

RTStop_TimedG = 2.000 * 3.500 min = 7.000 min