Determination of selenium by gas chromatography-mass spectrometry after formation of its volatile derivative and preconcentration using vortex-assisted dispersive liquid-liquid microextraction

Abstract

In this study, an easy and rapid derivatization and preconcentration method called vortex assisted dispersive liquid-liquid microextraction (VA-DLLME) was proposed for the determination of selenium by gas chromatography-mass spectrometry (GC-MS) after the formation of its volatile derivative with o-phenylenediamine (Se-PDA-FVD) in lake water samples. The gas chromatography system was utilized to determine inorganic selenium through the implementation of a developed derivatization procedure. The VA-DLLME method was employed to enhance the detection capability of the GC-MS system through preconcentration of the analyte. Derivatization and extraction procedure variables including pH and volume of buffer solution, volume of derivatizing agent, type and time period of mixing, type/volume of disperser and extraction solvents were optimized to improve the extraction output. Under the optimum derivatization/preconcentration conditions, the analytical performance of the VA-DLLME-Se-PDA-FVD-GC-MS method was determined. The limit of detection (LOD) and the limit of quantification (LOQ) were calculated as 2.2 ng mL(-1) and 7.3 ng mL(-1), respectively. Spiking experiments were performed with lake water to check the accuracy and applicability of the presented method. Percent recovery results for the spiked samples were found in the range of 80-106%.