Ultrasound-Assisted Dispersive Liquid–Liquid Microextraction (DLLME) Based on Solidification of Floating Organic Drop Using a Deep Eutectic Solvent for Simultaneous Preconcentration and Determination of Nickel and Cobalt in Food and Water Samples

Abstract

Ultrasound-assisted deep eutectic solvent-based dispersive liquid-liquid microextraction (UA-DES-DLLME-SFO) was employed with the solidification of floating organic drop to simultaneously preconcentrate and determine nickel and cobalt in food and water by flame atomic absorption spectrometry (FAAS). 2-(5-Bromo-2-pyridylazo)-5-(diethylamino) phenol (5-Br-PADAP) was employed as the chelating agent, while decanoic acid and dl-menthol were employed as deep eutectic solvents. The influence of extraction solvent type and volume, chelating agent content, pH, ionic strength, and ultrasonication duration was assessed on the microextraction efficiency. Moreover, analytical figures of merit of the approach were determined. The optimal condition resulted in detection limits of 0.3 µg/L and 0.4 µg/L, quantification limits of 1.1 µg/L and 1.3 µg/L, and preconcentration factors of 50 for Ni and Co, respectively. Relative standard deviations (n = 10) for 50.0 µg/L nickel and cobalt were 2.3% and 2.5%, respectively. The developed technique was employed to simultaneously extract and determine nickel and cobalt contents of food and water samples.

Keywords:

• Cobalt
• deep eutectic solvents
• flame atomic absorption spectrometry
• nickel
• solidification of floating organic drop

Additional information

Funding

The authors acknowledge the financial support from Payame Noor University.