ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRIC DETERMINATION OF COPPER IN NICKEL-BASE ALLOYS WITH VARIOUS CHEMICAL MODIFIERS

The analytical characteristics of copper in nickel-base alloys have be en investigated with electrothermal atomic absorption spectrometry. De uterium background correction was employed. The effects of various che mical modifiers on the analysis of copper were investigated. Organic m odifiers which included 2-(5-bromo-2-pyridylazo)-5-(diethylamino-pheno l) (Br-PADAP), ammonium citrate, 1-(2-pyridylazo)-naphthol, 4-(2-pyrid ylazo)resorcinol, ethylenediaminetetraacetic acid and Triton X-100 wer e studied. Inorganic modifiers palladium nitrate, magnesium nitrate, a luminum chloride, ammonium dihydrogen phosphate, hydrogen peroxide and potassium nitrate were also applied in this work. In addition, zircon ium hydroxide and ammonium hydroxide precipitation methods have also b een studied. Interference effects were effectively reduced with Br-PAD AP modifier. Aqueous standards were used to construct the calibration curves. The detection limit was 1.9 pg. Standard reference materials o f nickel-base alloys were used to evaluate the accuracy of the propose d method. The copper contents determined with the proposed method agre ed closely with the certified values of the reference materials. The r ecoveries were within the range 90-100% with relative standard deviati on of less than 10%. Good precision was obtained. (C) 1997 Elsevier Sc ience B.V.