ICP-MS-assisted nanoHPLC-electrospray Q/time-of-flight MS/MS selenopeptide mapping in Brazil nuts†
Abstract
A method was developed for the identification of selenium-containing peptides issued from proteins of a Se-rich (82.9 mg kg–1) foodstuff, Brazil nut (Bertholletia excelsa). A sample purification procedure was optimized to cope with the 100-fold excess of sulfur analogues and matrix interferences. It was based on the consecutive size-exclusion fractionation of proteins and tryptic peptides, and enrichment of the Se-containing fractions, prior to nanoHPLC-ES-Q/TOF MS/MS. The characteristic isotopic patterns of