title: Evaluation of the ALiPHAT method for PC-IDMS and correlation of limits-of-detection with nonpolar surface area.
abstract: PC-IDMS experiments for two peptides, laminin nonapeptide and the N-terminal tryptic peptide of prostate specific antigen, were performed utilizing a variety of alkylating reagents. These experiments were conducted to investigate how hydrophobicity influences the limits-of-detection (LOD) by altering their electrospray ionization response. Nonpolar surface areas were calculated for both peptides and all alkylating reagents to provide an estimate of the hydrophobicity of the differently alkylated peptides. Decreases in LOD by 2-fold were observed for both peptides between the best and worst performing combination of alkylating reagent. However, while an increase in hydrophobicity was found to aid in decreasing LOD to an extent, beyond a certain hydrophobicity, we observed a decrease.
authors.affiliation: W. M. Keck FT-ICR Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, USA.
authors.forename: D Keith
authors.initials: DK
authors.lastname: Williams
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Comins
authors.forename: Jerry L
authors.initials: JL
authors.lastname: Whitten
authors.forename: David C
authors.initials: DC
authors.lastname: Muddiman
mesh_terms: D000478:Alkylation; D000595:Amino Acid Sequence; D002138:Calibration; D002247:Carbon Isotopes / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007553:Isotope Labeling / Q000379:methods*; D007797:Laminin / Q000032:analysis / Q000737:chemistry; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D009587:Nitrogen Isotopes / Q000737:chemistry; D009842:Oligopeptides / Q000032:analysis / Q000737:chemistry*; D017430:Prostate-Specific Antigen / Q000737:chemistry; D012015:Reference Standards; D014357:Trypsin / Q000032:analysis / Q000737:chemistry
chemical_list: D002247:Carbon Isotopes; D007797:Laminin; D009587:Nitrogen Isotopes; D009842:Oligopeptides; D014357:Trypsin; D017430:Prostate-Specific Antigen