Apparatus and methods are disclosed for processing data transformed according to an invertible transform (e.g., using a Hadamard transform) multiplexing scheme. In one example of the disclosed technology, a computer-implemented method includes generating transformed data by applying a Hadamard transform to intensity data generated by modulating input of analytes into a mass spectrometer according to a pseudorandom sequence (PRS). The exemplary method further includes identifying at least one pair of symmetric intensity peaks in the transformed data based on the PRS and removing data associated with the pair of symmetric peaks from the transformed data to produce modified data, which can be used to identify, characterize, and/or quantify the composition of the sample. In some examples, the exemplary method further includes validating peaks in the transformed data based on comparing the location of peaks in the untransformed intensity data.
GOVERNMENT RIGHTS STATEMENT
 This invention was made with Government support under contract number DE-AC05-76RL01830 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.