title: Compound identification in gas chromatography/mass spectrometry-based metabolomics by blind source separation.
abstract: Metabolomics GC-MS samples involve high complexity data that must be effectively resolved to produce chemically meaningful results. Multivariate curve resolution-alternating least squares (MCR-ALS) is the most frequently reported technique for that purpose. More recently, independent component analysis (ICA) has been reported as an alternative to MCR. Those algorithms attempt to infer a model describing the observed data and, therefore, the least squares regression used in MCR assumes that the data is a linear combination of that model. However, due to the high complexity of real data, the construction of a model to describe optimally the observed data is a critical step and these algorithms should prevent the influence from outlier data. This study proves independent component regression (ICR) as an alternative for GC-MS compound identification. Both ICR and MCR though require least squares regression to correctly resolve the mixtures. In this paper, a novel orthogonal signal deconvolution (OSD) approach is introduced, which uses principal component analysis to determine the compound spectra. The study includes a compound identification comparison between the results by ICA-OSD, MCR-OSD, ICR and MCR-ALS using pure standards and human serum samples. Results shows that ICR may be used as an alternative to multivariate curve methods, as ICR efficiency is comparable to MCR-ALS. Also, the study demonstrates that the proposed OSD approach achieves greater spectral resolution accuracy than the traditional least squares approach when compounds elute under undue interference of biological matrices.
authors.affiliation: Metabolomics Platform - IISPV, Department of Electrical and Automation Engineering (DEEEA), Universitat Rovira i Virgili, Tarragona, Catalonia, Spain; CIBERDEM, Biomedical Research Networking Center in Diabetes and Associated Metabolic Disorders, Madrid, Spain. Electronic address: xavier.domingo@urv.cat.
authors.forename: Xavier
authors.initials: X
authors.lastname: Domingo-Almenara
authors.affiliation: B2SLAB, Department d'Enginyeria de Sistemes, Automàtica i Informàtica Industrial, CIBER-BBN, Universitat Politècnica de Catalunya, Barcelona, Catalonia, Spain.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Perera
authors.affiliation: Metabolomics Platform - IISPV, Department of Electrical and Automation Engineering (DEEEA), Universitat Rovira i Virgili, Tarragona, Catalonia, Spain; CIBERDEM, Biomedical Research Networking Center in Diabetes and Associated Metabolic Disorders, Madrid, Spain.
authors.forename: Noelia
authors.initials: N
authors.lastname: Ramírez
authors.affiliation: Metabolomics Platform - IISPV, Department of Electrical and Automation Engineering (DEEEA), Universitat Rovira i Virgili, Tarragona, Catalonia, Spain; CIBERDEM, Biomedical Research Networking Center in Diabetes and Associated Metabolic Disorders, Madrid, Spain.
authors.forename: Nicolau
authors.initials: N
authors.lastname: Cañellas
authors.affiliation: Metabolomics Platform - IISPV, Department of Electrical and Automation Engineering (DEEEA), Universitat Rovira i Virgili, Tarragona, Catalonia, Spain; CIBERDEM, Biomedical Research Networking Center in Diabetes and Associated Metabolic Disorders, Madrid, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Correig
authors.affiliation: Metabolomics Platform - IISPV, Department of Electrical and Automation Engineering (DEEEA), Universitat Rovira i Virgili, Tarragona, Catalonia, Spain; CIBERDEM, Biomedical Research Networking Center in Diabetes and Associated Metabolic Disorders, Madrid, Spain.
authors.forename: Jesus
authors.initials: J
authors.lastname: Brezmes
mesh_terms: D000465:Algorithms; D000596:Amino Acids / Q000097:blood; D019343:Citric Acid / Q000097:blood / Q000652:urine; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007294:Inositol / Q000097:blood / Q000652:urine; D007656:Ketoglutaric Acids / Q000097:blood / Q000652:urine; D016018:Least-Squares Analysis; D055442:Metabolome; D025341:Principal Component Analysis; D014508:Urea / Q000097:blood / Q000652:urine
chemical_list: D000596:Amino Acids; D007656:Ketoglutaric Acids; D019343:Citric Acid; D007294:Inositol; D014508:Urea
keywords: Compound deconvolution; Independent component analysis; Mass spectrometry; Metabolomics; Multivariate curve resolution; Orthogonal signal deconvolution