# US 9,752,973 B2 · Methods and systems for multiple charge correction of electrical mobility spectrometer data > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,973 B2 - Document ID: US9752973B2 - Status: Granted - Kind: B2 - Application number: 14/169,697 - Filed: 2014-01-31 - Published: 2014-07-31 - Granted: 2017-09-05 - Earliest claimed: 2013-01-31 - Assignees: Clarkson University - Applicants: Suresh Dhaniyala; Meilu He - Inventors: Suresh Dhaniyala; Meilu He - Web page: https://patentgrep.com/patent/US9752973B2 ## CPC - G01N 15/0266: {with electrical classification} - G01N 2015/0003: {Determining electric mobility, velocity profile, average speed or velocity of a plurality of particles} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract Systems and methods for determining particle size distribution from electrical mobility spectrometry (EMS) measurements in the presence of multiply charged particles. EMS data comprising zeroth order singly-charged particle size distribution information for one or more EMS channels is obtained and fitted using a Gumbel distribution function to obtain a fit function value. The obtained fit function value is used to correct for multiply-charged particle contribution to the received EMS data. ## Claims ### Claim 1 A method for determining particle size distribution from electrical mobility spectrometry (EMS) measurements in the presence of multiply charged particles, the method comprising the steps of: obtaining, via an electrical mobility spectrometer, EMS data, wherein the received EMS data comprises a particle signal for one or more EMS channels; calculating, using a processor, a zeroth order singly-charged particle size distribution from the particle signals in the one or more EMS channels; fitting, by the processor using a distribution function, the calculated zeroth order singly-charged particle size distribution to obtain a fit function value; correcting, by the processor using the obtained fit function value, for multiply-charged particle contribution to the received EMS data; and providing an output to a user comprising the fit and corrected particle size distribution. ### Claim 2 (depends on 1) The method of claim 1, wherein said EMS data is obtained using a scanning electrical mobility spectrometer. ### Claim 3 (depends on 1) The method of claim 1, wherein said EMS data is obtained without the use of an inertial impactor. ### Claim 4 (depends on 1) The method of claim 1, wherein said distribution function is a Gumbel distribution function. ### Claim 5 (depends on 1) The method of claim 1, wherein said distribution function is a lognormal or a bi-lognormal distribution function. ### Claim 6 (depends on 1) The method of claim 1, further comprising the step of interpolating the obtained zeroth order singly-charged particle size distribution into one or more finer channels to determine an appropriate number of fit points for said fitting step. ### Claim 7 (depends on 6) The method of claim 6, wherein if said interpolation determines that there is no detected mode size, or if said interpolation determines that a separate mode is beginning near the end of the obtained SMS data, then approximately the last 5 data points are used for said fitting step. ### Claim 8 (depends on 7) The method of claim 7, wherein said distribution function is a Gumbel distribution function, and further comprising the step of determining an initial value for Dpg, σg, and Nt for the Gumbel distribution function, where Nt is particle total number concentration, Dpg is the mode size, and σg is a scale parameter. ### Claim 9 (depends on 8) The method of claim 8, wherein said initial value for Dpg is equal to a particle size with the maximum concentration value. ### Claim 10 (depends on 8) The method of claim 8, wherein said initial value for Nt is a number concentration obtained from an integral of the singly-charged distribution dN/d log Dp,l. ### Claim 11 (depends on 1) The method of claim 1, wherein said correcting step is performed using multiple-charge correction. ### Claim 12 (depends on 1) The method of claim 1, further comprising the step of obtaining said EMS data using an EMS. ### Claim 13 A non-transitory machine readable storage medium having stored thereon a computer program for determining particle size distribution from electrical mobility spectrometry (EMS) measurements in the presence of multiply charged particles, the computer program comprising instructions for causing the machine to perform the steps of: obtaining, via an electrical mobility spectrometer, EMS data, wherein the received EMS data comprises a particle signal for one or more EMS channels; calculating a zeroth order singly-charged particle size distribution from the particle signals in the one or more EMS channels; fitting, using a distribution function, the calculated zeroth order singly-charged particle size distribution to obtain a fit function value; correcting, using the obtained fit function value, for multiply-charged particle contribution to the received EMS data; and providing an output to a user comprising the fit and corrected particle size distribution. ### Claim 14 (depends on 13) The non-transitory machine readable storage medium of claim 13, wherein said distribution function is a Gumbel distribution function. ### Claim 15 (depends on 13) The non-transitory machine readable storage medium of claim 13, wherein the computer program further comprises instructions for causing the machine to interpolate the obtained zeroth order singly-charged particle size distribution information into one or more finer channels to determine an appropriate number of fit points for said fitting step. ### Claim 16 A system configured to determine particle size distribution from electrical mobility spectrometry (EMS) measurements in the presence of multiply charged particles, the system comprising: an electrical mobility spectrometer configured to obtain EMS data, wherein the received EMS data comprises a particle signal for one or more EMS channels; a processor configured to: calculate a zeroth order singly-charged particle size distribution from the particle signals in the one or more EMS channels; fit, using a distribution function, the calculated zeroth order singly-charged particle size distribution to obtain a fit function value; and correct, using the obtained fit function value, for multiply-charged particle contribution to the received EMS data; and provide an output to a user comprising the fit and corrected particle size distribution. ### Claim 17 (depends on 16) The system of claim 16, wherein said EMS data is obtained using a scanning electrical mobility spectrometer. ### Claim 18 (depends on 16) The system of claim 16, wherein said EMS data is obtained without the use of an inertial impactor. ### Claim 19 (depends on 16) The system of claim 16, wherein said distribution function is a Gumbel distribution function. ### Claim 20 (depends on 16) The system of claim 16, wherein said processor is further configured to interpolate the obtained zeroth order singly-charged particle size distribution information into one or more finer channels to determine an appropriate number of fit points for said fitting step.