Effervescent tablets containing magnetic ionic liquids as a non-conventional extraction and dispersive agent for speciation of arsenite and arsenate in vegetable samples

Abstract

A novel and simple effervescence tablet-assisted magnetic ionic liquids-based microextraction (ETA-MILs-ME) combined with graphite furnace atomic absorption spectrometry (GFAAS) was developed for the speciation and determination of arsenite and arsenate in vegetable samples. A special effervescent tablet composed of magnetic ionic liquids and carbon dioxide sources was used for combining extractant dispersion and highly selective microextraction procedures into only one single step. In the ETA-MILs-ME step, highly selective separation of As(V) was achieved by chelation with ammonium molybdate followed by dispersion with 65 μL of magnetic ionic liquids. As(III) is not extracted at the same pH conditions and remained in the aqueous layer. After microextraction and phase separation by magnetic separation technology, the enriched As(V) in the magnetic ionic liquids was determined by GFAAS. The variables of interest in the ETA-MILs-ME procedure that affect the microextraction efficiency, such as the amount of the magnetic ionic liquids, composition of effervescent tablets, pH value of sample solution, amount of ammonium molybdate and matrix interference were systematically investigated. Under the optimum experimental conditions, the proposed methodology achieved 0.007 μg L−1 detection of limit and 97.9–105.8% recovery for As(V) at addition recovery tests. The combination of optimized ETA-MILs-ME with GFAAS was highly selective and sensitive and could be considered as an effective methodology for the separation of target inorganic As species form real vegetable samples.