An Electrospray Ionisation ion source and an Atmospheric Pressure Chemical Ionisation ion source are disclosed which comprise a probe 1 comprising three co-axial capillary tubes 2,3,3′. A blue-flame gas torch 6 is provided downstream of the probe 1 as a combustion source. An analyte solution is sprayed from an inner capillary tube 2 of the probe 1, a combustible gas is supplied to an intermediate capillary tube 3 of the probe 1 and oxygen or air is supplied to an outer capillary tube 3′ of the probe 1. The combustible gas supplies heat to aid desolvation of the droplets emerging from the probe 1 via combustion with the surrounding oxygen-containing atmosphere when combusted by the blue flame torch 6.