Atomic absorption spectrometric determination of trace zinc in alloys and biological samples after preconcentration with [1-(2-pyridylazo)-2-naphthol] on microcrystalline naphthalene.
An atomic absorption spectrometric method for the determination of trace amounts of zinc after adsorption of its [1-(2-pyridylazo)-2-naphthol] complex on microcrystalline naphthalene has been developed. This complex is adsorbed on microcrystalline naphthalene in the pH range 3.5-7.5 from large volumes of aqueous solutions of various alloys and biological samples with a preconcentration factor of 40. After filtration, the solid mass consisting of the zinc complex and naphthalene was dissolved with 5 ml of dimethylformamide and the metal was determined by flame atomic absorption spectrometry. Zinc can alternatively be quantitatively adsorbed on [1-(2-pyridylazo)-2-naphthol]-naphthalene adsorbent packed in a column and determined similarly. About 0.5 ng of zinc can be concentrated in a column from 200 ml of aqueous sample, where its concentration is as low as 2.5 pg ml-1. The calibration curve is linear in the range 0.1-6.5 ng ml-1 in dimethylformamide solution. Eight replicate determinations of 2 ng ml-1 of zinc gave a mean absorbance of 0.145 with a relative standard deviation of 1.5%. The sensitivity for 1% absorption was 0.061 ng ml-1. Various parameters, such as the effect of pH and the interference of a number of metal ions on the determination of zinc, have been studied in detail to optimize the conditions for the determination of zinc in various standard complex materials.
Taher
M A
MA
Department of Chemistry, Shahid Bahonar University, Kerman, Iran. taher@arg3.uk.ac.ir
D000327:Adsorption; D000497:Alloys / Q000737:chemistry*; D002614:Chelating Agents; D006197:Hair / Q000737:chemistry*; D006801:Humans; D009281:Naphthalenes; D009284:Naphthols; D010944:Plants / Q000737:chemistry*; D013054:Spectrophotometry, Atomic / Q000379:methods; D015032:Zinc / Q000032:analysis*
D000497:Alloys; D002614:Chelating Agents; D009281:Naphthalenes; D009284:Naphthols; C041728:1-(2-pyridylazo)-2-naphthol; C031721:naphthalene; D015032:Zinc