RESEARCH PAPER Magnetic ionic liquid-based dispersive liquid-liquid microextraction technique for preconcentration and ultra-trace determination of Cd in honey Emiliano F. Fiorentini 1 & Leticia B. Escudero 1 & Rodolfo G. Wuilloud 1 Received: 26 December 2017 /Revised: 7 March 2018 /Accepted: 28 March 2018 /Published online: 19 April 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract A simple, highly efficient, batch, and centrifuge-less dispersive liquid-liquid microextraction method based on a magnetic ionic liquid (MIL-DLLME) and electrothermal atomic absorption spectrometry (ETAAS) detection was developed for ultra-trace Cd determination in honey. Initially, Cd(II) was chelated with ammonium diethyldithiophosphate (DDTP) at pH 0.5 followed by its extraction with the MIL trihexyl(tetradecyl)phosphonium tetrachloroferrate(III) ([P 6,6,6,14 ]FeCl 4 ) and acetonitrile as dispersant. The MIL phase containing the analyte was separated from the aqueous phase using only a magnet. A back-extraction procedure was applied to recover Cd from the MIL phase using diluted HNO 3 and this solution was directly injected into the graphite furnace of ETAAS instrument. An extraction efficiency of 93% and a sensitivity enhancement factor of 112 were obtained under optimal experimental conditions. The detection limit (LOD) was 0.4 ng L -1 Cd, while the relative standard deviation (RSD) was 3.8% (at 2 μgL -1 Cd and n = 10), calculated from the peak height of absorbance signals. This work reports the first application of the MIL [P 6,6,6,14 ]FeCl 4 along with the DLLME technique for the successful determination of Cd at trace levels in different honey samples. Keywords Magnetic ionic liquids . Microextraction . Preconcentration . Cadmium . Honey Introduction Cadmium is a highly toxic element that occurs normally in nature at low concentrations. However, industrial activities can contribute to increase the abundance of Cd in the environ- ment, mainly due to contaminated wastewaters and the com- bustion of coals and oils, among others [1]. The accumulation of Cd in humans can provoke hypertension, osteoporosis, lung, liver, and kidney disorders [2]. Considering that the FAO/WHO Joint Committee on Food Additives establishes a maximum tolerable daily intake of Cd of 1.0–1.2 μg kg -1 body mass [3], it is necessary to regulate its concentration in all kind of foods and other types of samples that could repre- sent exposure routes. It has been demonstrated that Cd can be found in honey as a result of bees carrying the metal from nectar flowers to honey [4]. Therefore, the control of Cd con- centrations in honey and foods incorporating honey in their formulation acquires special attention not only for adults but also for infants and young children who are frequent con- sumers of honey and derived products. In this way, the MERCOSUR regulation in South America has established a maximum permissible limit for Cd in honey of only 0.1 μgg -1 [5]. In order to reach accurate and sensitive results in the determination of Cd in honey at these low concentration levels, a preconcentration step is often required before the detection of the metal by most instrumental detection techniques. Up to date, different extraction techniques have been reported for the preconcentration of Cd in honey samples, including solid phase extraction (SPE) [6, 7], cloud point Published in the topical collection Ionic Liquids as Tunable Materials in (Bio)Analytical Chemistry with guest editors Jared L. Anderson and Kevin D. Clark. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00216-018-1050-6) contains supplementary material, which is available to authorized users. * Rodolfo G. Wuilloud rwuilloud@mendoza–conicet.gob.ar 1 Laboratory of Analytical Chemistry for Research and Development (QUIANID), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Instituto Interdisciplinario de Ciencias Básicas (ICB), UNCUYO-CONICET, Padre J. Contreras 1300, 5500 Mendoza, Argentina Analytical and Bioanalytical Chemistry (2018) 410:4715–4723 https://doi.org/10.1007/s00216-018-1050-6