For research use only. Not for use in diagnostic procedures.
If the signal seems to be saturating during acquisition on a Triple Quad 5500 system using Analyst software, one option is to detune the acquisition method by using non-optimized collision energy values for the MRM transitions.
We recommend detuning the signal for an MRM transition through the collision energy (CE) parameter, which may display a more peak-like response with a clear apex over a range of voltages, and you may see a more robust decrease in signal by altering CE. If possible, refer to the CE ramp experiments completed when optimizing the acquisition parameters for each transition as a guide when selecting deoptimized CE values.
Adjusting the DP for each transition may also not be a very effective strategy to reduce instrument response. The response for DP when looking at a range of voltages on our newer instruments is not usually peak-shaped and is instead shaped like a plateau, so reducing the DP value may give the same response as a higher DP value if both voltages are on the plateau.
There are a few different types of saturation that can occur, including column saturation, detector saturation and in-source saturation. If possible, further diluting a sample can help overcome saturation issues. Dilution or the reduction in total sample volume may be considered, especially if the saturation issues are stemming from in-source saturation where the MS source is operating at its upper limit, creating the absolute maximum number of ions for a given amount of sample introduced. Use of alternative MRM transitions should also be considered to decreasing instrument response if they are not as robust as the transitions currently being used in the method.