Assay of Total Mercury in Commercial Food Supplements of Marine Origin by Means of DLLME/ICP-AES Araz Bidari & Mohammad Reza Ganjali & Yaghoub Assadi & Armin Kiani & Parviz Norouzi Received: 27 April 2011 /Accepted: 1 September 2011 /Published online: 17 September 2011 # Springer Science+Business Media, LLC 2011 Abstract In this work, we have developed a sensitive and cost-effective preconcentration and quantification method- ology for total mercury (Hg) at trace levels in food supplements of marine origin. Dispersive liquid–liquid microextraction was successfully employed for the precon- centration of mercury at trace levels prior to inductively coupled plasma atomic emission spectrometry. The mercury was extracted as mercury-1, 5-diphenyl-3-formazathiol complex, at pH 1.0 mediated by multidroplet formation of microextraction solvent assisted by disperser solvent. The lower limit of detection obtained under the optimal conditions was 0.24 μgL -1 . The calibration graphs were linear up to 500 μgL -1 . The precision of the method in terms of relative standard deviation was 4.8% for the concentration of 100 μgL -1 . In order to validate the proposed method, a certified reference material RTC-QCI- 049 was analyzed with the proposed procedure. Moreover, potential interference by 20 species was also evaluated. Keywords Total mercury . Food supplements . Marine . Dispersive liquid–liquid microextraction . Inductively coupled plasma atomic emission spectrometry Introduction Mercury (Hg) is considered to be one of the most toxic elements that are present in the environment as a result of natural processes and anthropogenic activities. Elemental Hg has got many applications, such as electrical devices, lamps, batteries, and dental amalgam (Bose-O’Reilly et al. 2008a; Bose-O’Reilly et al. 2008b; Petroczi and Naughton 2009; Schulz et al. 2009; Shah et al. 2010a; Yang and Wang 2008). The concern about Hg pollution in the marine environ- ment started with the well-known case of Minamata in Japan, where in the 1950s, many people were poisoned, and part of them even died after consuming fish and shellfish containing relatively high concentrations of mercury. Accurate data on mercury levels in food is therefore valuable in the assessment of Hg exposure risks from food consumption (clean, Voegborlo and Adimado 2010). The Joint FAO/WHO Expert Committee on Food Additives set provisional tolerable weekly intakes. The upper limits of estimated average dietary exposure to total mercury from foods other than fish and shellfish is 1 μg kg -1 body weight (bw) per week for adults and 4 μg kg -1 for children (Seventy-second meeting in Rome, 16–25th February 2010, summary and conclusion, Issued 16th March 2010). The concern about the mercury level in the environmental samples has encouraged the development of very sensitive, accurate, and precise analytical methods for its determination such as closed vessel microwave-assisted digestion system or solid phase extraction in combination with cold vapor atomic absorption spectrometry (Tuzen and Soylak 2005; Tuzen et al. 2009a, b, c). A. Bidari : M. R. Ganjali (*) : P. Norouzi Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran, Iran e-mail: ganjali@khayam.ut.ac.ir M. R. Ganjali : P. Norouzi Endocrinology & Metabolism Research Center, Tehran University of Medical Sciences, Tehran, Iran Y. Assadi : A. Kiani Department of Analytical Chemistry, Faculty of Chemistry, Iran University of Science and Technology, PO Box 16846-13114, Tehran, Iran Y. Assadi Electroanalytical Chemistry Research Center, Iran University of Science and Technology, PO Box 16846-13114, Tehran, Iran Food Anal. Methods (2012) 5:695–701 DOI 10.1007/s12161-011-9297-y