Ionic liquid modified silica sorbent for simultaneous separation and preconcentration of heavy metals from water and tobacco samples prior to their determination by flame atomic absorption spectrometry

Abstract

A new simple, fast, efficient and reusable ionic liquid-based solid phase extraction (IL-SPE) was developed and applied for simultaneous extraction/preconcentration of Cd(II), Co(II), Mn(II), Ni(II) and Pb(II) from water and cigarette tobacco samples as a prior step to their determination by flame atomic absorption spectrometry using micro-sample introduction system (micro-FAAS). In this method, a small amount of [BMIM][PF₆] (1-butyl-3-methylimidazolium hexafluorophosphate) was used as a surface modifier of silica substrate. A mini-column packed with the silica-supported ionic liquid sorbent (SiO₂–IL) was applied for simultaneous extraction of the metal ions mentioned above, which were complexed with 1-(2-pyridylazo)-2-naphthol (PAN) in the conditioned sample solution. This SiO₂–IL system, that employs a hybrid combination of ionic liquid extractive properties and supporting nature of the silica, contributed to increase extraction efficiency via ameliorating mass transfer yield.