Speciation Determination of Selenium in Seafood by High-Performance Ion-Exchange Chromatography-Hydride Generation-Atomic Fluorescence Spectrometry

A high-performance ion-exchange chromatography coupled with hydride generation-atomic fluorescence spectrometry (HPIEC-HG-AFS) method was developed for simultaneous speciation of selenium in seafood. Three selenium species including of selenocystine (Se-Cys), selenome-thionine (Se-Met), and selenite Se(IV) were separated on an anion-exchange column (PRP-X100) with eluent of 30 mM NH4H2PO4 and methanol (39:1, v/v) in 10 min at the flow rate of 1.0 mL min(-1). Variables affecting the HG-AFS detection of selenium species were optimized. The optimum conditions found were the following: reducing agent, 2.0 % of KBH4, and 5.0 % of HCl; lamp current, 90 mA; photomultiplier tube voltage, 280 V; flow rate of carrier gas, 300 mL min(-1); and shielding gas, 800 mL min(-1). Under the optimized conditions, the good linearity of calibration curves (R (2) > 0.999) between signal of fluorescence and concentration of selenium species was obtained in the range of detection limits (DLs), 80 mu g L-1, and the DLs of Se-Cys, Se-Met, Se(IV) were 1.66, 0.990, 1.10 mu g L-1, respectively. The repeatability of the method, expressed as relative standard deviation, was less than 5.0 % (n = 10), and the average recoveries for spiked test were from 87.3 to 103 % for three analytes in real seafood samples. The developed HPIEC-HG-AFS method was successfully applied for the speciation of selenium in seafood samples.