Precursor accumulation in a single charge state in mass spectrometry

A method for reducing the charge of precursor ions of the same compound that have different mass-to-charge ratio (m/z) values in order to continuously accumulate and transmit the precursor ions at a single m/z value, comprising:

• instructing an ion source device to ionize a compound of a sample using a processor, producing two or more precursor ions of the compound with different m/z values;
• instructing a reagent source device to supply charge reducing reagent using the processor;
• instructing an ion guide device positioned between a mass filter device and both the ion source device and the reagent source device to receive the two or more precursor ions from the ion source device and the charge reducing reagent from the reagent source device using the processor;
• instructing the ion guide device to apply an alternating current (AC) voltage and a direct current (DC) voltage to one or more electrodes of the ion guide device that creates a pseudopotential to trap the received two or more precursor ions with m/z values below a threshold m/z in the ion guide device and to, in turn, cause the trapped two or more precursor ions to be charge reduced by the received charge reducing reagent so that m/z values of the two or more precursor ions increase to a single m/z value above the threshold m/z using the processor;
• and
• instructing the ion guide device to apply the DC voltage to the one or more electrodes relative to a DC voltage applied to electrodes of the mass filter device that causes the two or more precursor ions with m/z values increased to the single m/z value to be continuously transmitted to the mass filter device using the processor.

A computer program product, comprising a non-transitory and tangible computer-readable storage medium whose contents include a program with instructions being executed on a processor so as to perform a method for reducing the charge of precursor ions of the same compound that have different mass-to-charge ratio (m/z) values in order to continuously accumulate and transmit the precursor ions at a single m/z value, the method comprising:

• providing a system, wherein the system comprises one or more distinct software modules, and wherein the distinct software modules comprise a control module;
• instructing an ion source device to ionize a compound of a sample using the control module, producing two or more precursor ions of the compound with different m/z values;
• instructing a reagent source device to supply charge reducing reagent using the control module;
• instructing an ion guide device positioned between a mass filter device and both the ion source device and the reagent source device to receive the two or more precursor ions from the ion source device and the charge reducing reagent from the reagent source device using the control module;
• instructing the ion guide device to apply an alternating current (AC) voltage and a direct current (DC) voltage to one or more electrodes of the ion guide device that creates a pseudopotential to trap the received two or more precursor ions with m/z values below a threshold m/z in the ion guide device and to, in turn, cause the trapped two or more precursor ions to be charge reduced by the received charge reducing reagent so that m/z values of the two or more precursor ions increase to a single m/z value above the threshold m/z using the control module;
• and
• instructing the ion guide device to apply the DC voltage to the one or more electrodes relative to a DC voltage applied to electrodes of the mass filter device that causes the two or more precursor ions with m/z values increased to the single m/z value to be continuously transmitted to the mass filter device using the control module.