Precolumn isotope dilution analysis in nanoHPLC-ICPMS for absolute quantification of sulfur-containing peptides.
A novel generic approach based on precolumn isotope dilution nanoHPLC-ICPMS analysis was developed for the accurate absolute quantification of sulfur-containing peptides. A 34S-labeled, species-unspecific sulfur spike (sulfate), noninteracting with analyte peptides under the optimized HPLC condition, was added directly to the chromatographic eluents. Thus a generic sulfur standard permanently present during analysis was used for peptide quantification. Interference-free detection of the 32S and 34S isotopes in ICPMS was achieved by eliminating O2+ ions in a collision cell using Xe gas at 130 microL min-1. The detection limit for sulfur was 45 microg L-1 which corresponded to 1-2 pmol of individual peptides. The method was validated by the analysis of a standard peptide solution showing high accuracy (recovery 103%) and good precision (RSD 2.1%). The combination of nanoHPLC-ICP IDMS with nanoHPLC-ESI MS/MS allowed the precise quantification and identification of sulfur-containing peptides in tryptic digests of human serum albumin and salt-induced yeast protein (SIP18) at the picomole level.
Schaumlöffel
Dirk
D
Group of Bio-Inorganic Analytical Chemistry, CNRS UMR 5034, Hélioparc, 2, Av. Pr. Angot, F-64053 Pau, France. dirk.schaumloeffel@univ-pau.fr
Giusti
Pierre
P
Preud'Homme
Hugues
H
Szpunar
Joanna
J
Łobiński
Ryszard
R
D002851:Chromatography, High Pressure Liquid / Q000379:methods; D006801:Humans; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D010455:Peptides / Q000032:analysis* / Q000737:chemistry*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry; D012680:Sensitivity and Specificity; D012709:Serum Albumin / Q000032:analysis / Q000096:biosynthesis / Q000737:chemistry; D013455:Sulfur / Q000032:analysis*; D013460:Sulfur Isotopes; D013997:Time Factors
D010455:Peptides; D029701:Saccharomyces cerevisiae Proteins; D012709:Serum Albumin; D013460:Sulfur Isotopes; D013455:Sulfur