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Peak quantification in surface‐enhanced laser desorption/ionization by using mixture models
Author(s) -
Dijkstra Martijn,
Roelofsen Han,
Vonk Roel J.,
Jansen Ritsert C.
Publication year - 2006
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200600181
Subject(s) - mass spectrometry , ionization , analytical chemistry (journal) , desorption , time of flight mass spectrometry , biological system , chemistry , surface enhanced laser desorption/ionization , chromatography , sample (material) , laser , materials science , electrospray ionization , physics , optics , protein mass spectrometry , adsorption , ion , organic chemistry , biology
Surface‐enhanced laser desorption/ionization (SELDI) time of flight (TOF) is a mass spectrometry technology for measuring the composition of a sampled protein mixture. A mass spectrum contains peaks corresponding to proteins in the sample. The peak areas are proportional to the measured concentrations of the corresponding proteins. Quantifying peak areas is difficult for existing methods because peak shapes are not constant across a spectrum and because peaks often overlap. We present a new method for quantifying peak areas. Our method decomposes a spectrum into peaks and a baseline using so‐called statistical finite mixture models. We illustrate our method in detail on 8 samples from culture media of adipose tissue and globally on 64 samples from serum to compare our method to the standard Ciphergen method. Both methods give similar estimates for singleton peaks, but not for overlapping peaks. The Ciphergen method overestimates the heights of such peaks while our method still gives appropriate estimates. Peak quantification is an important step in pre‐processing SELDI‐TOF data and improvements therein will pay off in the later biomarker discovery phase.