Data sets for isotope pattern grouping of LC-HRMS peaks with package nontarget. Based on a vast set of PubChem molecular formulas, quantized (a) m/z, (b) m/z differences, (c) intensity ratios and (d) marker centroids of simulated centroid pairs are listed for different instrument resolutions.
List of 8
$ R_set : MS Instrument with a specific resolution=f(m/z) setting
$ R_param : Ignore, for debugging
$ isotope_key : Isotope categories
$ charge_key : Charge (z) categories
$ Quant_param : Quantization parameters
$ Quant : Quantized data in categories of dominant isotope, charge and presene/absence of a marker mass
$ mass_slots : m/z windows used for filtering
$ intrat_slots: m/z windows used for filtering
The isotope pattern centroids of several million organic molecular formulas from the PubChem database were calculated for various classes of adducts. Molecular formulas were filtered to be unique and only to contain C, H, O, N, Cl, Br, K, Na, S, Si, F, P and/or I. The resulting >250 million centroid pairs from individual patterns were then categorized for their dominant isotopologues, charge and the possible presence of another centroid of higher intensity than that of the pair (marker peak). Within these categories, data on centroid pair (a) m/z, (b) m/z differences, (c) intensity ratios and (d) marker m/z was quantized by a recursive partitioning procedure. These resulting compressed data representation was extended by nearest neigbour estimates in the above dimensions (a) to (d) to account for queries with molecular formulas possibly not represented by the PubChem set. Query access to the data is provided through a tree-like space-partitioning structure for hyperrectangles.
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