A method of mass spectrometry comprising: setting an ionisation efficiency of an ion source to a first value and/or setting an attenuation factor of an attenuation device to a first value and/or setting a gain of an ion detector or ion detection system to a first value; and then separating or filtering ions according to a first physico-chemical property and separating or filtering ions according to a second physico-chemical property and obtaining a multi-dimensional array of data; determining the most intense ion peak within one or more multi-dimensional subsets of said multi-dimensional array of data; and determining whether or not said most intense ion peak would cause saturation of an ion detector or an ion detection system or would otherwise adversely affect the operation of said ion detector or ion detection system; wherein if it is determined that said most intense ion peak would cause saturation of said ion detector or ion detection system or would otherwise adversely affect the operation of said ion detector or ion detection system then said method further comprises: (i) adjusting said ionisation efficiency of said ion source to a second value and/or adjusting said attenuation factor of said attenuation device to a second value and/or adjusting said gain of said ion detector or ion detection system to a second value; (ii) obtaining mass spectral data wherein the adjustment of said ionisation efficiency of said ion source and/or the adjustment of said attenuation factor of said attenuation device and/or the adjustment of said gain of said ion detector or ion detection system alters the intensity of substantially all ions which are detected by said ion detector or ion detection system substantially equally and substantially irrespective of the mass to charge ratio of said ions; and then (iii) scaling the intensity of said mass spectral data based upon the degree to which said ionisation efficiency of said ion source and/or said attenuation factor of said attenuation device and/or said gain of said ion detector or ion detection system was increased or reduced. setting an ionisation efficiency of an ion source to a first value and/or setting an attenuation factor of an attenuation device to a first value and/or setting a gain of an ion detector or ion detection system to a first value; and then separating or filtering ions according to a first physico-chemical property and separating or filtering ions according to a second physico-chemical property and obtaining a multi-dimensional array of data; determining the most intense ion peak within one or more multi-dimensional subsets of said multi-dimensional array of data; and determining whether or not said most intense ion peak would cause saturation of an ion detector or an ion detection system or would otherwise adversely affect the operation of said ion detector or ion detection system; wherein if it is determined that said most intense ion peak would cause saturation of said ion detector or ion detection system or would otherwise adversely affect the operation of said ion detector or ion detection system then said method further comprises: (i) adjusting said ionisation efficiency of said ion source to a second value and/or adjusting said attenuation factor of said attenuation device to a second value and/or adjusting said gain of said ion detector or ion detection system to a second value; (ii) obtaining mass spectral data wherein the adjustment of said ionisation efficiency of said ion source and/or the adjustment of said attenuation factor of said attenuation device and/or the adjustment of said gain of said ion detector or ion detection system alters the intensity of substantially all ions which are detected by said ion detector or ion detection system substantially equally and substantially irrespective of the mass to charge ratio of said ions; and then (iii) scaling the intensity of said mass spectral data based upon the degree to which said ionisation efficiency of said ion source and/or said attenuation factor of said attenuation device and/or said gain of said ion detector or ion detection system was increased or reduced. (i) adjusting said ionisation efficiency of said ion source to a second value and/or adjusting said attenuation factor of said attenuation device to a second value and/or adjusting said gain of said ion detector or ion detection system to a second value; (ii) obtaining mass spectral data wherein the adjustment of said ionisation efficiency of said ion source and/or the adjustment of said attenuation factor of said attenuation device and/or the adjustment of said gain of said ion detector or ion detection system alters the intensity of substantially all ions which are detected by said ion detector or ion detection system substantially equally and substantially irrespective of the mass to charge ratio of said ions; and then (iii) scaling the intensity of said mass spectral data based upon the degree to which said ionisation efficiency of said ion source and/or said attenuation factor of said attenuation device and/or said gain of said ion detector or ion detection system was increased or reduced.