Solidified floating organic drop microextraction for determination of trace amounts of zinc in water samples by flame atomic absorption spectrometry

A simple and efficient liquid-phase microextraction technique was developed using ultrasound-assisted emulsification solidified floating organic drop microextraction (USAE-SFODME) combined with flame atomic absorption spectrometry, for the extraction and determination of trace amounts of zinc in water samples. 1-(2-Pyridylazo)-2-naphthol (PAN) was used as chelating agent. The main parameters affecting the performance of USAE-SFODME, such as type of extraction solvent as well as extraction volume, time, temperature, pH, the amount of the chelating agent, and salt effect were investigated and optimized. Under optimized experimental conditions a preconcentration factor of 76 was obtained using only 5.0 mL of water sample. The calibration graph was linear in the range from 20 to 450 μg L−1 with a detection limit of 0.79 μg L−1. The relative standard deviation for ten replicate measurements of 20 and 300 μg L−1 of zinc were 4.0 and 2.8 %, respectively. The proposed method was applied to tap water, sea water, and river water, and its accuracy was assessed through the analysis of certified reference water and recovery experiments.