Study of mercury–selenium interaction in chicken liver by size exclusion chromatography inductively coupled plasma mass spectrometry

Abstract

In order to estimate metal distribution patterns in biomolecules of different sizes and their possible modification after long-term Hg and Se exposition, multi-elemental distribution of the cytosols of chicken livers were evaluated. For this purpose 72 chickens were fed under different controlled conditions. Chickens were exposed to Hg(II) and MeHg added to feed with or without selenium supplementation. Size-exclusion chromatography with ICP-MS detection was developed for multielemental (S, P, Cu, Zn, Se, Mn, Fe and Hg) speciation in chicken liver cytosol and optimisation of the separation parameters (25 mM Tris-HCl buffer, 50 mM KCl, pH 6.8, 1 ml min⁻¹) was carried out. The liver extracts were injected into the column four times each and the variation between the runs was small (RSD <10%). The recovery of the chromatographic step varied between 82–102%, indicating some interaction between the liver extracts and the column material. S, Cu, Zn, Fe, Se and Hg appeared mainly associated to high and medium-molecular weight species (>300–45 kDa), whereas Mn is mainly associated to high (116 kDa) and low (0.03 kDa) molecular weight species and P is mainly associated to low molecular weight species (5.5 kDa). Changes in the subcellular distribution and distribution patters caused by long-term Hg–Se administration have been discussed.