Extractive Electrospray Ionization Mass Spectrometry for Rapid Analysis of Organic and Inorganic Selenium in Honey

Selenium, a crucial trace element for human health, plays a vital role in maintaining well-being. Its insufficiency can cause various diseases, highlighting the need for adequate selenium intake in daily diets. Honey, containing diverse selenium compounds, serves as a beneficial selenium supplement. By leveraging the distinctive physicochemical properties of honey, we employed reactive extractive electrospray ionization mass spectrometry (EESI-MS) to rapidly analyze the presence of both organic selenium (selenomethionine) and inorganic selenium (sodium selenite) in diluted honey samples. We successfully identified selenomethionine (SeMet) and sodium selenite. Calibration curves constructed for SeMet and sodium selenite demonstrated excellent linear relationships within the concentration range of 0.5 to 50 µg/L. The limits of detection (LOD) for SeMet and sodium selenite were determined to be 2.94 µg/kg and 5.18 µg/kg, respectively, while the limits of quantification (LOQ) were 9.52 µg/kg and 17.4 µg/kg, respectively. Furthermore, spiked recoveries ranged from 90.6% to 105%. The average analysis time is 2 min. This study presents a precise, rapid, and convenient method for selenium determination in diluted honey. Given the limited sample size in this preliminary study, future research with larger cohorts is required to validate our findings.