Determination of Selenomethionine, Selenocystine, and Methylselenocysteine in Egg Sample by High Performance Liquid Chromatography—Inductively Coupled Plasma Mass Spectrometry

Abstract

The deficiency of selenium in dietary is recognized as a global problem. Eggs, as one of the most widely consumed food products, were readily enriched with selenium and became an important intake source of selenium for humans. In order to better understand the speciation and bioaccessibility of selenium in eggs, a simple and reliable approach that could be easily used in a routine laboratory was attempted to develop for analyzing selenium species. Three of organic selenium species (selenocystine, methylselenocysteine, and selenomethionine) in liquid whole egg were completely released by enzymatic hydrolysis and detected by high performance liquid chromatography in combination with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). All the parameters in enzymatic hydrolysis and separation procedures were optimized. The effect of matrix in analysis was critically evaluated by standard addition calibrations and external calibrations. Under the optimal conditions, the spike recoveries of selenium species at 0.1–0.4 μg g−1 spike levels all exceeded 80%. This method was successfully applied to the determination of selenium species in fresh egg and cooked eggs.

Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages

“…Although several food categories have been evaluated for their contribution to the presence of Se in the diet, including cereals, meat and vegetables, eggs have received less attention. Aiming to fill this gap, a group of researchers 149 undertook a thorough investigation of analytical procedures suitable to determine the total Se content as well as those of selected Se species (Se IV , Se VI , SeCys 2 , SeMet and MeSeCys), in raw and cooked whole eggs. Four extractants (H 2 O; 0.1 mol L −1 HCl; 0.1 mol L −1 NaOH; 25 mmol L −1 CH 3 COONH 4 buffer–5% MeOH (v/v)), as well as enzymatic hydrolysis with protease XIV, were studied, of which the last gave the best results.…”

Atomic spectrometry update: review of advances in elemental speciation

“…For instance, NH 4 Ac provided the highest extraction efficiency, however SeMet was rather unstable in this extraction medium. A complete and detailed study on Se speciation in eggs by HPLC-ICP-MS measurements has been presented by Zhao et al 108 Four types of chromatographic columns for performing separation were evaluated (RPC18 columns and a Hamilton PRPX-100 column). An Agilent SB-Ag (4.6 mm × 250 mm, 5 μm) was selected for further studies as provided the highest peak intensities and the best resolution for the five Se-species tested (SeCys2, MeSeCys, Se IV , Se VI and SeMet).…”

Advances in Accurate Quantification Methods in Food Analysis

“…The last two manuscripts are about nutritional analytes. Wang's group described an analysis method for three organic selenium (Se) species (selenomethionine, selenocystine and methylselenocysteine) in egg samples [18]. Since Se was widely incorporated into protein, enzymatic hydrolysis with protease XIV was optimized in sample preparation.…”