Meaning
Algorithmic comparison metrics evaluate similarity between experimental mass spectra and computerized reference spectrum libraries. Identification of unknown extractables in medical plastics relies on the mass spectral match score to quantify confidence when assigning molecular identities to chromatogram peaks. This mathematical index governs non-target screening workflows in gas chromatography mass spectrometry testing.
The score reflects pattern agreement across ion fragments and does not provide absolute confirmation without authentic reference standard injections.
Spectral Similarity
Vector correlation algorithms compare ion fragment mass-to-charge ratios and relative peak abundances. A high mass spectral match score indicates near-identical fragmentation patterns between the unknown polymer migrant and library reference entry. Isomeric plasticizers often yield matching scores above 900, requiring chromatographic retention index matching to differentiate specific isomers.
Threshold Criteria
Regulatory compliance frameworks set minimum statistical thresholds for compound identification in food contact screening. An experimental mass spectral match score below 700 triggers manual spectral review or secondary mass spectrometry analysis. Low match scores frequently stem from co-eluting polymer oligomers distorting baseline ion ratios.
Deconvolution Efficiency
Overlapping chromatographic peaks alter pure compound spectra and corrupt automated library searches. Deconvolution software isolates target compound spectra, improving the resulting mass spectral match score in complex polyolefin extracts. Clean spectral deconvolution reduces false negative reporting in routine additive screening.
