A method of mass and/or ion mobility spectrometry comprising: accumulating ions for a first period of time (T1) one or more times so as to form one or more first groups of ions; accumulating ions for a second period of time (T2) one or more times so as to form one or more second groups of ions, wherein said second period of time (T2) is less than said first period of time (T1); separating according to one or more first physico-chemical properties one or more of said first and/or second groups of ions using a separation device; analysing said one or more first groups of ions to generate one or more first data sets; analysing said one or more second groups of ions to generate one or more second data sets; and determining whether said one or more first data sets comprise saturated and/or distorted data; wherein when it is determined that said one or more first data sets comprise saturated and/or distorted data, then said method further comprises: replacing said saturated and/or distorted data from said one or more first data sets with corresponding data from said one or more second data sets; wherein: the method comprises performing said step of accumulating said ions so as to form one or more of said one or more first and/or second groups of ions and at the same time performing said step of separating according to one or more first physico-chemical properties; said step of separating ions according to said one or more first physico-chemical properties comprises operating said separation device in a cyclical manner so as to repeatedly separate respective groups of ions according to said one or more first physico-chemical properties; and said steps of accumulating and analysing said ions are performed repeatedly in synchronism with the cycle time of said separation device; wherein in a given period of time said method comprises forming n first groups of ions and forming m second groups of ions, wherein n is greater than m. accumulating ions for a first period of time (T1) one or more times so as to form one or more first groups of ions; accumulating ions for a second period of time (T2) one or more times so as to form one or more second groups of ions, wherein said second period of time (T2) is less than said first period of time (T1); separating according to one or more first physico-chemical properties one or more of said first and/or second groups of ions using a separation device; analysing said one or more first groups of ions to generate one or more first data sets; analysing said one or more second groups of ions to generate one or more second data sets; and determining whether said one or more first data sets comprise saturated and/or distorted data; wherein when it is determined that said one or more first data sets comprise saturated and/or distorted data, then said method further comprises: replacing said saturated and/or distorted data from said one or more first data sets with corresponding data from said one or more second data sets; the method comprises performing said step of accumulating said ions so as to form one or more of said one or more first and/or second groups of ions and at the same time performing said step of separating according to one or more first physico-chemical properties; said step of separating ions according to said one or more first physico-chemical properties comprises operating said separation device in a cyclical manner so as to repeatedly separate respective groups of ions according to said one or more first physico-chemical properties; and said steps of accumulating and analysing said ions are performed repeatedly in synchronism with the cycle time of said separation device; wherein in a given period of time said method comprises forming n first groups of ions and forming m second groups of ions, wherein n is greater than m. <EOS>