Quadrupole devices

A method of operating a quadrupole device comprising:

• operating the quadrupole device in a first mode of operation, wherein ions within a first mass to charge ratio range are selected and/or transmitted by the quadrupole device;
• and
• operating the quadrupole device in a second mode of operation, wherein ions within a second different mass to charge ratio range are selected and/or transmitted by the quadrupole device;
• wherein operating the quadrupole device in the first mode of operation comprises operating the quadrupole device using a first calibration function;
• and
• wherein operating the quadrupole device in the second mode of operation comprises operating the quadrupole device using a second different calibration function.

Apparatus comprising:

• a quadrupole device;
• and
• a control system;
• wherein the control system is configured:
• (i) to operate the quadrupole device in a first mode of operation, wherein ions within a first mass to charge ratio range are selected and/or transmitted by the quadrupole device;
• and
• (ii) to operate the quadrupole device in a second mode of operation, wherein ions within a second different mass to charge ratio range are selected and/or transmitted by the quadrupole device;
• wherein the control system is configured to operate the quadrupole device in the first mode of operation by operating the quadrupole device in a normal mode of operation wherein a main drive voltage is applied to the quadrupole device, or by operating the quadrupole device in a first X-band or Y-band mode of operation wherein a main drive voltage and two or more auxiliary drive voltages are applied to the quadrupole device;
• and
• wherein the control system is configured to operate the quadrupole device in the second mode of operation by operating the quadrupole device in a second X-band or Y-band mode of operation wherein a main drive voltage and two or more auxiliary drive voltages are applied to the quadrupole device;
• wherein in the first and/or second X-band or Y-band mode of operation:
• the main drive voltage has a main drive voltage frequency Ω and the two or more auxiliary drive voltages comprise a first auxiliary drive voltage having a first frequency ωex1, and a second auxiliary drive voltage having a second different frequency ωex2, wherein the main drive voltage frequency Ω and the first and second frequencies ωex1, ωex2 are related by ωex1=v1Ω, and ωex2=v2Ω, where v1 and v2 are constants.