Chamber Current and Capillary Current


How are the capillary current and chamber current measured?  I see that they are measured in nanoAmps and microAmps, respectively.  Are they measured through a detector?  And if so, where is this detector located?

The instrument we use is a Triple Quadrupole 6495C.  


  • Hi Good Day,  The capillary and Chamber voltages are applied by same Power supply but the voltages are off by 500Volts and when it comes to measurement there is no special detector to measure this , When the Charged analytes are diverted towards the capillary becasue of the Electrostatic forces ( applied by V cap and V Chamber )  most of the Ions will pass and at the same time some if the Charged ions strike the spray shield and capillary Cap ( these ions will get discharged resulting drop in the voltage which power supply senses this and try to maintain the Voltage by pumping current this is measured as Nano Amps and Micro Amps) hope this clarifies . Basically this is the indirect measurement on power supply



  • Hi Srini, thank you very much for your answer.  So does this mean that as the spray shield and capillary cap get more residue buildup from sample contamination, more current will be applied?

  • Sorry what i mean here is - its like if water getting drained from Tank -  to maintain the level in the tank more liquid will flow - in this case it is not applying current what we see indirect way of looking at number of ions in the source or number of ions forming - if its dirty spray shield and cap - i suppose you will see less feed back current becasue the charged ions will not get discharged on the plate but will get struck on the dirt - ( i guess)

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