Determination of cobalt by air-assisted liquid–liquid microextraction

Abstract

A rapid and selective technique for extraction, preconcentration and determination of trace amounts of cobalt in water and pharmaceutical samples by air-assisted liquid–liquid microextraction combined with flame atomic absorption spectrometry is proposed. 1-Nitroso-2-naphthol is used as a complexing agent and 1-octanol as an extraction solvent. Parameters relevant for analytical effectivity, i.e. pH of sample solution, concentration of complexing agent, volume of extraction solvent, and number of extraction cycles are optimized using a Box–Behnken design. At optimum conditions, a dynamic linear range of 5–600 µg L⁻¹ is obtained, with a limit of detection of 1.2 µg L⁻¹. The method is used for determination of Co(II) in environmental water and pharmaceutical samples.

Keywords:

• Cobalt
• air-assisted liquid–liquid microextraction
• flame atomic absorption spectrometry
• Box–Behnken design
• water and pharmaceutical samples

Disclosure statement

No potential conflict of interest was reported by the authors.