Determination of selenomethionine, selenocysteine, and inorganic selenium in eggs by HPLC–inductively coupled plasma mass spectrometry

• Published in: Analytical and bioanalytical chemistry Vol. 397; no. 2; pp. 731 - 741
• Main Authors: Lipiec, Elżbieta, Siara, Grzegorz, Bierla, Katarzyna, Ouerdane, Laurent, Szpunar, Joanna
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-05-2010; Springer; Springer Verlag
• Subjects: Amino acids; Analytical Chemistry; Animals; Biochemistry; Characterization and Evaluation of Materials; Chemical Sciences; Chemistry; Chemistry and Materials Science; Chickens; Chromatographic methods and physical methods associated with chromatography; Chromatography, High Pressure Liquid - methods; Denaturation; Eggs; Eggs - analysis; Exact sciences and technology; Food Science; High performance liquid chromatography; Laboratory Medicine; Limit of Detection; Mass spectrometry; Mass Spectrometry - methods; Mathematical analysis; Monitoring/Environmental Analysis; Original Paper; Other chromatographic methods; Proteins; Selenium; Selenium - analysis; Selenocysteine - analysis; Selenomethionine; Selenomethionine - analysis; Spectrometric and optical methods; Chicken egg; Supplementation; Selenium; Selenium speciation; Size; HPLC chromatography; Product; Time; Inductive coupling plasma spectrometry; Electrospray; Design; Sample preparation; Detection limit; Aves; Selenium IV; Speciation; Quantitative analysis; Trace analysis; Purification; Coupled method; Denaturation; Digestion; 5'-End; Protein; Gel permeation chromatography; Vertebrata; Reversed phase chromatography; Simultaneous measurement; Isolation; Chicken; Selenites; Mass spectrometry
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-010-3544-8

A method for the simultaneous determination of selenomethionine (SeMet), selenocysteine (SeCys), and selenite [Se(IV)] in chicken eggs was developed. A sample preparation protocol including defatting, protein denaturation, and carbamidomethylation was optimized in order to achieve complete protein digestion and to avoid SeCys losses. Quantification was carried out by reversed-phase HPLC–inductively coupled plasma mass spectrometry (ICP MS) after quantitative isolation of the selenium-containing fraction by size-exclusion liquid chromatography. The detection limits were 0.06, 0.003, and 0.01 µg g
−1
(dry weight) for SeCys, Se(IV) and SeMet, respectively, and the precision was 5–10%. The end products of carbamidomethylation of the different selenium species were identified for the first time by electrospray QTOF MS after custom-designed 2D HPLC purification. Differences in selenium speciation in egg yolk and white were highlighted, the yolk containing more SeCys and the white more SeMet. An insight into selenium bioaccessibility in eggs was obtained by digestion with simulated gastric and gastrointestinal juices and size-exclusion HPLC-ICP MS.
Figure
Selenium speciation in chicken eggs