Vol:.(1234567890) Journal of Analysis and Testing (2018) 2:98–105 https://doi.org/10.1007/s41664-017-0046-0 1 3 ORIGINAL PAPER Simultaneous Determination of Bismuth, Lead, and Iron in Water Samples by Optimization of USAEME and ICP–OES via Experimental Design Taghi Sahraeian 1,2  · Hassan Sereshti 2  · Ahmad Rohanifar 2 Received: 7 October 2017 / Accepted: 21 December 2017 / Published online: 19 January 2018 © The Nonferrous Metals Society of China 2018 Abstract Ultrasound-assisted emulsifcation–microextraction followed by inductively coupled plasma–optical emission spectrometry was utilized for simultaneous pre-concentration and trace detection of lead, bismuth, and iron in water samples. Disodium N,N  -bis(salicylidene)ethylenediamine and trichloroethylene were used as chelating agent and extraction solvent, respectively. The parameters of interest were volume of extraction solvent, temperature, and concentrations of salt and chelating agent. A fractional factorial design was developed to identify these parameters and how they vary with one another. The results dem- onstrated that the concentrations of salt and chelating agent afected extraction efciency. Subsequently, a central-composite design was used to acquire optimum levels of efective parameters. The optimal conditions were 160.7 mg L -1 and 1.77% (w/v) for concentration of chelating agent and salt, respectively. The linear dynamic ranges were determined to be 1–1000 μ g L -1 for Pb and Bi, and 10–1000 μg L -1 for Fe. The correlation coefcient ( R 2 ) was 0.990–0.995. The limits of detection were 0.54–0.78 μg L -1 . The relative standard deviation (concentration = 200 μg L -1 , n = 8) was in the range of 2.0–4.3%. This method was successfully applied for the trace detection of Pb, Bi, and Fe in freshwater samples of waterfall and spring and satisfactory relative recoveries (96.2–99.6%) were obtained. Keywords Ultrasound-assisted emulsifcation–microextraction · Bismuth · Lead · Iron · Disodium N · N  -bis (salicylidene) ethylenediamine · Inductively coupled plasma–optical emission spectroscopy · Experimental design 1 Introduction Heavy metals have the potential to be caustic to human health, non-biodegradable, and often than not accumulate in vital human organs, where they can negatively afect the body over a long period of time. Urbanization, indus- trial development, and heavy trafc lead to contamination of waters with heavy metals [1]. Among the heavy metals, lead is one of the most perilous ones, and in the recent years, concerns have increased over the concentration of lead in drinking and natural waters. Lead has reportedly given rise to harmful efects in the body such as reduction of enzymatic activity, kidney dysfunction, and neuromuscular difculties [2]. Bismuth has been used in pharmaceuticals for the treat- ment of Helicobacter pylori-induced gastritis. While bismuth was proven useful for remedying symptoms of gastritis, negative efects on human health have been reported. These side efects include nephropathy, osteoarthropathy, hepatitis, and disorders of the nervous system. The widespread use of bismuth in pharmaceuticals has led to an increased exposure by the environment [3]. Iron is vital to most living organ- isms. It is an essential part of hemoglobin: the red coloring agent of the blood that transports oxygen through our bod- ies. A high concentration of iron, however, can be harmful, because it is reversibly oxidized and reduced. This prop- erty, while essential for its metabolic functions, makes iron potentially hazardous because of its ability to participate in the generation of powerful oxidant species such as hydroxyl radical [4]. Numerous studies have assessed the association between the iron status and risk of coronary heart disease. A hereditary haemochromatosis or iron-overload condition has been identifed as an independent risk factor for myocardial * Taghi Sahraeian sahraeian.1@osu.edu 1 Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA 2 Department of Chemistry, Faculty of Science, University of Tehran, Tehran, Iran