regarding less sensitivity of LC-MS-TOF

[bedse.gaurav]

which parameters we need to change and up to what extent (flow of drygas, nebulizer,potential of quadrupole and hexapole, collision energy) in LC-MS-TOF to increase the response of the drug e.g. hydrochlorothiazide

[MIB_EO]

All of them!

MS intensity response is quite sample specific, all the parameters you list can make a difference.

However:
I would start with the ESI needle capillary V, probe position and cone or source V settings.
Then I would adjust the gas flow
Finally I would adjust the collision energy.

I would not adjust the hex or Quad settings, as these tend to be more instrument specific than sample specific.

All parameters can be adjusted by +/- 50% of their current value. be aware that some parameters interact eg porbe position and source V.