There are several ways to approach PA (Pulse-Analog ratio) Factor determination. You can run the PA factor calibration during Startup using Agilent provided solutions or make your own custom PA solutions. To successfully calibrate a PA factor, element concentration must be high enough such that the detector can see the ion signal in both pulse mode and analog mode. These concentrations are therefore not trace level and there is a risk that running these high concentration solutions may actually elevate the background for some elements (contaminate the system).
It is therefore recommended to now determine PA factors inside the batch during calibration. MassHunter can automatically determine the PA factors using just the calibrations standards. This minimizes the elements that are analyzed on the system to only those in the calibration. It also limits the number of high concentration standards to those already used, minimizing possible sources of contamination.
Also, by determining PA factors in the batch, we have the added option of determining tune mode specific PA factors. Because kinetic energy differs for elements by tune mode, the resulting PA factors can be slightly different for elemental ions in different tune modes. When determining PA factors in a batch, select Independent PA Factors and MassHunter will determine a PA factor for each elemental ion per tune mode, providing a more accurate result.
Attached is a brief description of PA Factor determination from MassHunter software.