Preconcentration of Nickel(II) by a Mini-Flow System with a Novel Ternary Oxide Solid Phase and Flame Atomic Absorption Spectrometry

ABSTRACT

A SiO₂/Al₂O₃/Sb₂O₅ mixed oxide was synthesized via a sol-gel method and applied to the on-line preconcentration of Ni(II) with determination by flame atomic absorption spectrometry. The mixed oxide was characterized by infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, thermogravimetric analysis, and the specific surface area. Analysis was performed by percolating 20.0 mL of sample at pH 7.1 through 100 mg of SiO₂/Al₂O₃/Sb₂O₅ packed into a mini-column at 9.5 mL min⁻¹. Under the optimum conditions, a preconcentration factor of 77.5-fold, linear dynamic range from 5.0 to 270.0 µg L⁻¹, and limits of detection and quantification of 0.48 and 1.61 µg L⁻¹ were obtained. The effects of several concomitant ions were evaluated and no interferences were observed. The method was employed for the analysis of water with good recoveries (92.9–100.6%) and the accuracy was verified by using a marine sediment certified reference material (MESS-3).

KEYWORDS:

• Flame atomic absorption spectrometry
• nickel
• on-line flow solid phase extraction