Optimization of a hydrophobic solid-phase extraction interface for matrix-assisted laser desorption/ionization

• Published in: Journal of mass spectrometry. Vol. 33; no. 11; pp. 1141 - 1147
• Main Authors: Brockman, Adam H., Shah, Nina N., Orlando, Ron
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.11.1998; Wiley
• Subjects: Aminoacids, peptides. Hormones. Neuropeptides; Analytical, structural and metabolic biochemistry; Biological and medical sciences; coupled methods; Cytochrome c Group - chemistry; Fundamental and applied biological sciences. Psychology; Half-Life; Hydrolysis; Indicators and Reagents; matrix-assisted laser desorption/ionization mass spectrometry; Proteins; Renin - metabolism; solid-phase extraction; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Surface Properties; Trypsin; Trace analysis; Solid phase extraction; Chymotrypsin(drug); Peptides; Coupled method; Matrix assisted laser desorption ionization; Chemical enrichment; Cytochrome c; Separation method; Analysis method; Peptide fragment; Polypeptide; Mass spectrometry; Interface
• ISSN: 1076-5174; 1096-9888
• DOI: 10.1002/(SICI)1096-9888(1998110)33:11<1141::AID-JMS732>3.0.CO;2-U

Matrix‐assisted laser desorption/ionization (MALDI) probe surfaces derivatized with octadecanethiol (C18) can be used as hydrophobic solid‐phase extraction devices to isolate and desalt biopolymers directly on the probe surface. Using quantitative MALDI, it was possible to determine the approximate amount of peptide that bound to C18 surfaces and thus to calculate a surface density. It was determined that the amount of peptide bound at the probe surface was independent of the analyte concentration in the immersion solution (from high‐ to sub‐ng ml‐1 concentrations), but rather was dependent on the immersion time of the surface as it was exposed to the analyte. The capacity of C18‐derivatized probes to bind biopolymers in fixed amounts frees the analyst from the necessity for adjusting analyte concentration through multiple step procedures such as serial dilution or vacuum drying. This time savings result in an overall increase in the efficiency of the MALDI technique. © 1998 John Wiley & Sons, Ltd.