Integrated electrospray ion source

A process for ionizing a sample, comprising:

• providing a first electrospray ion probe configured for accommodating a sample flow rate in nanoflow range, said probe having a first emitter for ionizing said sample,
• providing a second electrospray ion probe configured for accommodating a sample flow rate in a range above said nanoflow range, said probe having a second emitter for ionizing said sample, wherein the emitter of each of said ion probes is fixedly positioned relative to a discharge tip of the ion probe,
• measuring electrical resistance across a first and second openings of an ion source, into which the first and second electrospray ion probes are configured to be coupled,
• receiving values of the measured electrical resistance,
• determining if any of said first and second probes is respectively coupled into the first and second openings,
• introducing a sample into one of said first or second ionization probes, and
• activating one or more of the first and second emitters of the first and second ionization probes, powered according to the determining if any of said first and second probes is coupled to the respective first and second openings, so as to ionize at least a constituent of said sample.