Use of dimethylglyoxime, acenaphthenequinone dioxime and mixed ligands of dimethylglyoxime and acenaphthenequinone dioxime supported on naphthalene for the pre-concentration and determination of nickel in alloys, tea and water samples using atomic absorption spectrometry

Abstract

Solid chelating compounds such as dimethylglyoxime (DMG), acenaphthenequinone dioxime (ANDO) and their mixed ligands (DMG-ANDO) supported on naphthalene were found to provide a rapid and economical route to the pre-concentration of nickel in alloys and biological and natural water samples. Nickel formed chelates with DMG, ANDO and DMG-ANDO supported on microcrystalline naphthalene in a column at pH in the ranges 5.0–9.4, 6.1–11.0 and 7.1–11.0, respectively. The metal complex and naphthalene were dissolved out from the column using 3 ml of dimethylformamide-nitric acid and the absorbance was measured by an atomic absorption spectrometer at 232 nm. The calibration graphs obtained were linear over the concentration range 5–40 µg (for DMG) and 2–30 µg (for ANDO and DMG-ANDO) of nickel in 3 ml of the final solution. The precision and detection limits of the method were studied for DMG, ANDO and DMG-ANDO. The sensitivities for 1% absorption were 0.132, 0.104 and 0.100 µg ml^–1 for DMG, ANDO and DMG-ANDO, respectively (0.153 µg ml^–1 for the direct determination from the aqueous medium by atomic absorption spectrometry). The method was used for the determination of nickel in various standard reference materials and water samples from different natural sources.