Nanoparticle baseline and particle detection threshold determination through iterative outlier removal

A system for iterative determination of outlier data from a spectrometry data set, comprising:

• a spectrometry sample analyzer configured to receive a fluid sample containing nanoparticles from a sample source and to generate a spectrometry data set associated with detected ion signal intensity over time;
• one or more computer processors;
• and
• a non-transitory computer readable-medium bearing one or more instructions for execution by the one or more computer processors to cause the one or more computer processors to perform the steps of:
• generating from the spectrometry data set, via one or more computer processors, a raw data set that includes a count distribution of counts of ion signal intensity and a frequency of the ion signal intensity of each count;
• iteratively removing, via the one or more computer processors, ion signal intensity values that exceed an outlier threshold value associated with a sum of a first multiple of an average of the count distribution of ion signal intensity and a first multiple of a standard deviation of the count distribution of ion signal intensity until no count values exceed the outlier threshold value to provide a background data set;
• and
• setting, via the one or more computer processors, a nanoparticle baseline intensity value as a sum of a second multiple of an average of the background data set and a second multiple of a standard deviation of the background data set, wherein the first multiple of the standard deviation of the count distribution of ion signal intensity differs from the second multiple of a standard deviation of the background data set.