A dual-labelling strategy for integrated ICPMS and LIF for the determination of peptides

In this proof-of-concept study, a novel dual-labelling strategy for conjugating -SH and -NH2 of a peptide was developed, in which an element tag (1,4,7,10-tetraazacyclododecane-1,4,7-trisacetic acid-10-maleimidoethylacetamide loaded with europium) and a fluorescent tag (fluorescein isothiocycanate) were employed. Its feasibility was demonstrated using HPLC-UV/ESI-MS for evaluating labelling-efficiency and HPLC-ICPMS with Eu-153 isotope dilution as well as CE-LIF for the determination of peptides.