The H-ESI spray insert includes the sheath gas and auxiliary gas plumbing, a needle insert, and a nozzle. Sample and solvent enter the nozzle through the needle insert, which is a metal electrospray capillary that extends from the sample inlet to approximately 1.2 mm (0.05 in.) past the end of the nozzle. The H-ESI spray insert delivers the sheath gas and auxiliary gas to the nozzle. The MS applies a large negative or positive voltage (typically ±3 to ±5 kV) to the needle, which sprays the sample solution into a fine mist of charged droplets.

CAUTION

To prevent heat damage to the spray insert, ensure that the gas flows are always on and set to the following minimum recommended settings when the vaporizer temperature is above 275 °C.

  • Sheath gas (Arb): 30
  • Aux Gas (Arb): 10

 

The following figure shows the H-ESI spray insert with a magnified view of the nozzle.

Figure H-ESI spray insert
H-ESI nozzle (close-up view)

 

The following figure shows the H-ESI needle insert removed from the H-ESI spray insert.

Figure H-ESI needle insert removed from the H-ESI spray insert

 

For information about the gases, see Sheath Gas, Auxiliary gas, and Sweep gas.