title: Evaluation of affinity-based serum clean-up in mass spectrometric analysis: Plastic vs monoclonal antibodies.
abstract: Mass spectrometric assays are now of great relevance for trace compound analysis in complex matrices such as serum and plasma samples. Especially in the quantification of low abundant protein-biomarkers, the choice of the sample preparation is crucial. In the present paper immunocapture and Molecular Imprinted Polymers (MIPs) have been applied in the determination of pro-gastrin-releasing peptide, a Small Cell Lung Cancer marker. These affinity-based techniques were compared in terms of matrix effect, limits of detection, repeatability and extraction specificity. In addition, protein precipitation was included for comparison as it is a typical sample preparation method of biological matrices. The results highlighted differences in the methods' performance and specificity, strongly affecting the outcome of the mass spectrometric determination. Plastic and monoclonal antibodies confirmed to be sensitive and specific sample preparations able to determine ProGRP at clinical relevant concentration, although only the use of monoclonal antibodies allowed the reliable quantification of ProGRP at reference levels (8pM). In addition better insight in the specificity of the three sample preparation techniques was gained. This might also be of interest for other biological applications.
authors.affiliation: Department of Pharmaceutical Chemistry, University of Oslo, Oslo, Norway.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Rossetti
authors.affiliation: Department of Pharmaceutical Chemistry, University of Oslo, Oslo, Norway.
authors.forename: Maren C S
authors.initials: MC
authors.lastname: Levernæs
authors.affiliation: Department of Pharmaceutical Chemistry, University of Oslo, Oslo, Norway.
authors.forename: Léon
authors.initials: L
authors.lastname: Reubsaet
authors.affiliation: Department of Pharmaceutical Chemistry, University of Oslo, Oslo, Norway. Electronic address: t.g.halvorsen@farmasi.uio.no.
authors.forename: Trine G
authors.initials: TG
authors.lastname: Halvorsen
mesh_terms: D000911:Antibodies, Monoclonal / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000097:blood*; D001774:Blood Chemical Analysis / Q000379:methods*; D002853:Chromatography, Liquid; D006801:Humans; D013058:Mass Spectrometry; D010455:Peptides / Q000097:blood*; D010969:Plastics / Q000378:metabolism*; D011498:Protein Precursors / Q000097:blood*; D012680:Sensitivity and Specificity; D044967:Serum / Q000737:chemistry; D055752:Small Cell Lung Carcinoma / Q000097:blood*
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D010455:Peptides; D010969:Plastics; D011498:Protein Precursors; C047897:gastrin-releasing peptide precursor
keywords: Biological matrices; Immunocapture; LC–MS; Molecularly imprinted polymers; Protein precipitation; Sample preparation