Simultaneous determination of aluminum, copper, iron and zinc in Oscillatoria, Juncus littoralis tissues and wetland water samples by ultrasound-assisted emulsification-microextraction combined with ICP-OES

Abstract

Ultrasound-assisted emulsification microextraction (USAEME) followed by inductively coupled plasma-optical emission spectrometry (ICP-OES) for simultaneous extraction, preconcentration and determination of trace levels of aluminum, copper, iron and zinc in Oscillatoria, Juncus littoralis tissues and wetland water samples is presented. Sodium diethyldithiocarbamate trihydrate (Na-DDTC·3H₂O) was used as a chelating agent and tetrachloroethylene was selected as an extraction solvent. The effective parameters of the USAEME method including volume of extraction solvent, ultrasonic time, salt concentration, temperature, concentration of ligand and pH were investigated by a fractional factorial design. The results showed that temperature had no considerable effect on the efficiency. A Box-Behnken design (BBD) was applied to optimize the effective parameters. The optimal conditions were obtained as 48 μL for volume of extraction solvent, 6 min for ultrasonic time, 16.6 (w/v %) for salt concentration, 1440 mg L⁻¹ for concentration of the ligand and 7 for pH. The linear dynamic range (LDR) was 1–1000 μg L⁻¹ with determination coefficient of 0.994–0.998. The limits of detection (LODs) and relative standard deviations (RSDs) were 0.64–0.91 μg L⁻¹ and 2.6–5.3%, respectively. The method was successfully applied to the determination of Al, Cu, Fe and Zn in real environmental samples and satisfactory relative recoveries (92–99%) were obtained.