A multi-technique platform for the quantification and identification of selenoneine with a focus on HPLC-HG-AFS

Abstract

Selenoneine, a naturally occurring form of selenium (Se) in biota, has recently raised considerable interest in the fields of nutrition, drug development and environmental research. Selenoneine has a strong antioxidant capacity which makes it a potential Se supplement for humans or farm animals. There is a lack of a reliable and cost-effective online speciation methodology for the determination of such a biologically relevant Se species. In this study, a method has been developed for the simultaneous analysis of selenoneine and other organic Se species. It is based on the online coupling of reversed-phase liquid chromatography, ultraviolet radiation, thermal treatment, hydride generation and atomic fluorescence spectrometry (HPLC-UV-TT-HG-AFS). Quantitative determination of selenoneine by external calibration and its separation from commonly found organic Se species (selenomethionine, Se-methyl-selenocysteine) was achieved. The proposed methodology resulted in a linear response (R² > 0.999) for a concentration range of 5–100 μgSe L⁻¹ and a limit of detection of 0.5 μgSe L⁻¹. The repeatability was 0.8 %, with a reproducibility of 1.6 %. This analytical approach is versatile, cost-effective, and fast with a chromatographic runtime of less than 12 min. The high selectivity of HPLC-ICP-MS, combined with the species identification power of HPLC-ESI-MS/MS was found invaluable for gaining further speciation insights and confirming the results obtained by HPLC-UV-TT-HG-AFS. The developed approach could serve as useful tool for routine selenoneine analysis in biological samples as shown here with the analysis of seabird liver extracts.