matchSamples2DB {metaMS} | R Documentation

## Match pseudospectra from several samples to an in-house DB (GC-MS)

### Description

Compare experimental results to a database of pseudospectra. The result is a nested list, containing for every pseudospectrum in every sample either an index of a corresponding pattern in the DB (if a hit is found) or nothing (if no hit is found). Not meant to be called directly by the user.

### Usage

    matchSamples2DB(xset.msp, DB, settings, quick)

### Arguments

`xset.msp` | An object containing a list of pseudospectra.
`DB` | The in-house database.
`settings` | The settings, in the form of a list.
`quick` | Logical. If TRUE, scaling of the pseudospectra (which is necessary for comparing to the database) will be done once using all masses in the pseudospectrum. This mode is routinely applied when comparing with a database of artefacts such as bleeding patterns or plasticizers. When comparing with a database of chemical standards, however, only peaks smaller than the molecular weight (+ 4, to allow for isotopes) should be taken into account in the scaling, and hence the scaling needs to be re-done for every comparison. This is _not_ so quick...

### Value

A list object, with one element for each experimental sample. Every element again is a list with an entry for each pseudospectrum from that sample: if the element is empty, there is no match with the DB - a number points to the DB entry that gives a hit. Elements can contain more than one number; these will be split into one “best” annotation and “alternative” annotations in function `annotations2tab`.

### Author(s)

Ron Wehrens

[Package metaMS version 1.22.0 Index]