Systems and Methods for Recording Average Ion Response
Systems and methods are provided for calculating and storing an average amplitude response for each peak of a mass spectrum during data acquisition. A mass analyzer is instructed to analyze N extractions of an ion beam, producing N sub-spectra. For each sub-spectrum of the N sub-spectra, a nonzero amplitude from an ADC detector subsystem is counted as one ion, producing a count of one for each ion. The ADC amplitudes and counts of the N sub-spectra are summed, producing a spectrum that includes a summed ADC amplitude and a total count for each ion. For each ion of the spectrum, an estimated ion count is calculated from a Poisson distribution of the total count of each ion for the N sub-spectra. For each ion of the spectrum, an average amplitude response is calculated by dividing the summed amplitude by the estimated ion count and stored.
1 . A system for calculating and storing an average amplitude response for each peak of a mass spectrum during data acquisition, comprising:
an ion source that ionizes sample molecules producing a beam of ions;
a mass analyzer that includes an analog-to-digital converter (ADC) detector subsystem analyzes the beam of ions; and
a processor in communication with the mass analyzer that
(a) instructs the mass analyzer to analyze N extractions of the ion beam, producing N sub-spectra,
(b) for each sub-spectrum of the N sub-spectra, counts a nonzero amplitude from the ADC detector subsystem as one ion, producing a count of one for each ion of each sub-spectrum,
(c) sums the ADC amplitudes and counts of the N sub-spectra, producing a spectrum that includes a summed ADC amplitude and a total count for each ion of the spectrum,
(d) for each ion of the spectrum, calculates an estimated ion count from a Poisson distribution of the total count of each ion for the N sub-spectra,
(e) for each ion of the spectrum, calculates and stores an average amplitude response by dividing the summed amplitude by the estimated ion count, and
(f) executes step (a) again.
2 . The system of claim 1 , wherein the mass analyzer further comprises a TDC detector subsystem and the processor performs step (b) by reading the TDC detector subsystem.
3 . The system of claim 1 , wherein the mass analyzer comprises a quadrupole.
4 . The system of claim 1 , wherein the mass analyzer comprises an ion trap.
5 . The system of claim 1 , wherein the mass analyzer comprises a time-of-flight (TOF) mass analyzer.
6 . The system of claim 1 , wherein for each ion of the spectrum, the processor calculates an estimated ion count from a Poisson distribution of the total count for the N sub-spectra, if N exceeds the total count by a threshold level.
7 . The system of claim 1 , wherein an average amplitude response of an ion of the spectrum is used to distinguish the ion from another ion with same mass but a different charge, or to distinguish the ion from another ion with same mass but from an different class of compounds.
8 . A method for calculating and storing an average amplitude response for each peak of a mass spectrum during data acquisition, comprising:
(a) instructing a mass analyzer to analyze N extractions of a ion beam using a processor, producing N sub-spectra, wherein the mass analyzer includes an analog-to-digital converter (ADC) detector subsystem and analyzes a beam of ions produced by an ion source that ionizes sample molecules;
(b) for each sub-spectrum of the N sub-spectra, counting a nonzero amplitude from the ADC detector subsystem as one ion using the processor, producing a count of one for each ion of each sub-spectrum;
(c) summing the ADC amplitudes and counts of the N sub-spectra using the processor, producing a spectrum that includes a summed ADC amplitude and a total count for each ion of the spectrum;
(d) for each ion of the spectrum, calculating an estimated ion count from a Poisson distribution of the total count of each ion for the N sub-spectra using the processor;
(e) for each ion of the spectrum, calculating and storing an average amplitude response by dividing the summed amplitude by the estimated ion count using the processor; and
(f) executing step (a) again using the processor.
9 . The method of claim 8 , wherein step (b) is performed by reading a TDC detector subsystem using the processor.
10 . The method of claim 8 , wherein the mass analyzer comprises a quadrupole.
11 . The method of claim 8 , wherein the mass analyzer comprises an ion trap.
12 . The method of claim 8 , wherein the mass analyzer comprises a time-of-flight (TOF) mass analyzer.
13 . The method of claim 8 , wherein for each ion of the spectrum, calculating an estimated ion count from a Poisson distribution of the total count for the N sub-spectra using the processor is performed, if N exceeds the total count by a threshold level.
14 . The method of claim 8 , wherein an average amplitude response of an ion of the spectrum is used to distinguish the ion from another ion with same mass but a different charge, or to distinguish the ion from another ion with same mass but from an different class of compounds.
15 . 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 calculating and storing an average amplitude response for each peak of a mass spectrum during data acquisition, the method comprising:
(a) providing a system, wherein the system comprises one or more distinct software modules, and wherein the distinct software modules comprise a control module and an analysis module;
(b) instructing a mass analyzer to perform a series of N extractions of a beam of ions using the control module, producing N sub-spectra, wherein the mass analyzer includes an analog-to-digital converter (ADC) detector subsystem and analyzes a beam of ions produced by an ion source that ionizes sample molecules;
(c) for each sub-spectrum of the N sub-spectra, counting a nonzero amplitude from the ADC detector subsystem as one ion using the analysis module, producing a count of one for each ion of each sub-spectrum;
(d) summing the ADC amplitudes and counts of the N sub-spectra using the analysis module, producing a spectrum that includes a summed ADC amplitude and a total count for each ion of the spectrum;
(e) for each ion of the spectrum, calculating an estimated ion count from a Poisson distribution of the total count of each ion for the N sub-spectra using the analysis module;
(f) for each ion of the spectrum, calculating and storing an average amplitude response by dividing the summed amplitude by the estimated ion count using the analysis module; and
(g) executing step (a) again using the control module.
16 . The computer program product of claim 15 , wherein step (b) is performed by reading a TDC detector subsystem using the processor.
17 . The computer program product of claim 15 , wherein the mass analyzer comprises a quadrupole.
18 . The computer program product of claim 15 , wherein the mass analyzer comprises an ion trap.
19 . The computer program product of claim 15 , wherein the mass analyzer comprises a time-of-flight (TOF) mass analyzer.
20 . The computer program product of claim 15 , wherein for each ion of the spectrum, the method calculates an estimated ion count from a Poisson distribution of the total count for the N sub-spectra using the processor is performed, if N exceeds the total count by a threshold level.