Selenium speciation in ginger using capillary electrophoresis online coupled with electrothermal atomic absorption spectrometry

Abstract

A novel and sensitive selenium speciation in cultivated ginger rhizomes was developed using capillary electrophoresis coupled with electrothermal atomic absorption spectrometry. Influencing parameters were experimentally investigated. Under optimal conditions, SeMet, SeCys₂, Se^IV, and Se^VI were completely separated when using capillary electrophoresis electrothermal atomic absorption spectrometry. Detection limits of SeMet, SeCys₂, Se^IV, and Se^VI were 1.7, 2.2, 0.89, and 0.97 ng mL⁻¹, respectively. The recoveries ranged from 95.6% to 104%. The RSD of peak height was observed to be smaller than 5%. When selenium enrichment was used on ginger, SeMet, Se^IV, and Se^VI could be detected in the first month; in the second month, the concentration of SeCys₂, as well as the concentrations of SeMet, Se^IV, and Se^VI, could be determined. Ginger absorbs SeO₃²⁻ and SeO₄²⁻ at different rates; they could be converted into the organic selenium species.