Question

Both MALDI and ESI can be used to look at large molecules. ESI is often coupled with ion traps or quadrupole mass spectrometers, but MALDI is not. Why?

A.Quadrupoles and ion traps don’t work with pulsed sources.

B.You can’t have a low-pressure ion source with a quadrupole or ion trap.

C.The m/z range is too small with quadrupoles and ion traps

D.You can’t get adequate resolution with a trap.

Answer 1

Both MALDI and ESI can be used to look at large molecules. ESI is often coupled with ion traps or quadrupole mass spectrometers, but MALDI is not because C.The m/z range is too small with quadrupoles and ion traps as low mass accuracy in resolution due to linear time of flight(TOF) spectrum which means   ions with the same charge can attained the different amount of kinetic energy which leads to different (m/z) ratio of ions which have different initial velocities.