Ni(II) analysis in food and environmental samples by liquid-liquid microextraction combined with electro-thermal atomic absorption spectrometry

This paper presents a novel method which is simple, highly selective, and sensitive for rapid pre-concentration and microextraction of ultra-trace levels of Ni2 + in natural foods and waters samples. In this research, ligand 1-p-tolyl-3-(3-(trifluoromethyl)phenyl)triaz-1-ene 1-oxide (PTTO) was used as a complexing agent. After extraction, the sedimented phase was directly injected into (ETAAS) for determination of Ni2 +. Some effects of various experimental factors on pre-concentration and determination were investigated using central composite design as an optimization method. Factors relevant to the pre-concentration, complex formation, and determination, such as types and volume of extraction solvent, disperser solvent, ionic strength (salt effect), extraction time, and concentration of the chelating agent were investigated and optimized. The calibration curve was linear over the nickel concentration range of 0.2-80 ng mL− 1 with the detection limit of 0.03 ng mL− 1. Relative standard deviation (R.S.D) for 10 replicate determinations at 2.0 ng mL− 1 of nickel was 2.18%. Finally, the proposed method was applied to the extraction and determination of Ni2 + in a variety of natural samples with satisfactory results.