Correcting drift effects in lc-ms data based on retention time

A computing system for correcting drift in retention times of compound signals in chromatography-mass spectrometry (chromatography-MS) data, the system comprising:

• a. a communication interface that receives EICs of portions of each of a plurality of MS chromatograms, wherein the portions of the plurality of chromatograms bear the same m/z value;
• and
• b. a processor that executes instructions stored in memory, wherein the processor executes the instructions to:
• i. split a reference extracted ion chromatogram (EIC) selected from a plurality of EICs into a plurality of time increments, wherein each EIC of the plurality of EICs contains a mass-to-charge (m/z) signal feature having the same m/z value;
• ii. for each remaining EIC, shift data points of the remaining EIC by a first time increment of the plurality of time increments to generate a query EIC;
• iii. determining, for the query EIC, a non-overlapping subset of data points comprising data points lying outside an intersection between the reference EIC and the query EIC and an overlapping subset of data points comprising data points of the query EIC that overlap with data points of the reference EIC;
• iv. generate a scoring function value based on the non-overlapping subset of data points, the overlapping subset of data points, or both subsets of data points;
• v. iteratively repeat steps (ii) to (iv) for each of the plurality of time increments to generate a plurality of scoring function values;
• vi. determine an optimal time increment that corresponds to the drift of the m/z signal feature by minimizing the scoring function value based on the non-overlapping subset of data points, maximizing the scoring function value based on the overlapping subset of data points, or both;
• and
• vii. correct the query EIC by shifting the query EIC by the optimal time increment.

A non-transitory, computer-readable storage medium, having embodied thereon a program executable by a processor to perform a method for correcting drift in retention times of compound signals in chromatography-mass spectrometry (chromatography-MS) data, the method comprising:

• a. splitting a reference extracted ion chromatogram (EIC) selected from a plurality of EICs into a plurality of time increments, wherein each EIC of the plurality of EICs contains a mass-to-charge (m/z) signal feature having the same m/z value;
• b. for each remaining EIC, shifting data points of the remaining EIC by a first time increment of the plurality of time increments to generate a query EIC;
• c. determining, for the query EIC, a non-overlapping subset of data points comprising data points lying outside an intersection between the reference EIC and the query EIC and an overlapping subset of data points comprising data points of the query EIC that overlap with data points of the reference EIC;
• d. generating a scoring function value based on the non-overlapping subset of data points, the overlapping subset of data points, or both subsets of data points;
• e. iteratively repeating steps (b) to (d) for each of the plurality of time increments to generate a plurality of scoring function values;
• f. determining an optimal time increment that corresponds to the drift of the m/z signal feature by minimizing the scoring function value based on the non-overlapping subset of data points, maximizing the scoring function value based on the overlapping subset of data points, or both;
• and
• g. correcting the query EIC by shifting the query EIC by the optimal time increment.