Determination of nickel in water samples by graphite furnace atomic absorption spectrometry after ionic liquid-based dispersive liquid-liquid microextraction preconcentration

Abstract

A novel method based on ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) preconcentration and graphite furnace atomic absorption spectrometry detection was developed for the determination of nickel in lake water, tap water, and seawater samples. In the proposed method, 1<2-pyridylazo>2-naphthol (PAN) was used as the chelating agent, acetone as the dispersive solvent, and ionic liquid (l-butyl-3-methylimidazolium hexafluorophosphate) as the extraction solvent instead of a volatile organic solvent. Some parameters influencing the ILDLLME extraction efficiency of nickel and its subsequent determination, such as the type and volume of IL and dispersive solvent, pH, the amount of PAN, extraction time and centrifuge time, were investigated. Under the optimum conditions, the enrichment factor was 67, the detection limit for nickel was 18 ng L -1 (3σ), and the relative standard deviation (RSD) was 6.5% (n7, c5.0 ng mL -1). The method was successfully applied to the determination of trace amounts of nickel in different water samples.