Precolumn Isotope Dilution Analysis in nanoHPLC−ICPMS for Absolute Quantification of Sulfur-Containing Peptides

Abstract

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.

ICP‐MS‐Based strategies for protein quantification

“…Charge-transfer reactions between an oxygen ion and a xenon atom are considered as a reactive mechanism , respectively (Pröfrock, Leonhard, & Prange, 2003). Recently, precolumn sulfur IDA in nano-HPLC coupled to ICP-MS was developed to measure sulfur-containing peptides, where the sulfur spike ( 34 S) was added directly into the chromatographic eluent (Schaumlöffel et al, 2007). In contrast to the postcolumn isotope dilution, in which the spike is added after the chromatographic separation, the precolumn isotope dilution reduces the broadening of the chromatographic peaks and stabilizes the spike flow.…”

Online isotope dilution and inductively coupled plasma mass spectrometry: from elemental to species quantification

“…93 The original scheme of the instrumental setup (Figure 7) presents the pre-column spike in a nano flow system to perform SUID. The reverse phase nano HPLC column was connected to a nano flow nebulizer installed in a small spray chamber (3 cm 3 ) with total sample transportation to the plasma at 300 ± 5 nL min -1 .…”

Rapid Determination of Low-level Sulfite in Dry Vegetables and Fruits by LC-ICP-MS

“…Dynamic reaction cell (DRC) technique with O 2 makes the determination of total sulphur and sulphur species easier (Bandura et al, 2002;Lin and Jiang, 2009;Schaumlöffel et al, 2007;Stürup et al, 2006;M. Wang et al, 2007;Yang and Jiang, 2004) Our work aimed to develop a simple, sensitive and reliable method for the determination of sulfite in dry vegetables and fruits.…”