With a 35V in-source CID and a capillary temperature of 250 °C, LTP was significantly softer than APCI. ESI was not included in the comparison, but LTP was compared to ESI in a subsequent study . We thus deduced stepwise that the average internal energy in APCI was from 230% (at 150 °C) to 330% (at 250 °C) of that in ESI at 250°C.