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Please use this identifier to cite or link to this item: http://eprint.iitd.ac.in/handle/2074/590

Title: Preconcentration of trace cobalt with the ion pair of 2-(5-bromo-2 paridylazo)-5-diethylaminophenol and tetraphenylborate onto microcrystallin naphthalene column method and its determination by derivative spectrophotometry
Authors: Pancras, J Patrick
Puri, Bal Krishan
Taher, Mohammad Ali
Dehzoei, Ali Mostafavi
Sheibani, Ali
Keywords: Cobalt determination
Derivative spectrophotometry
Standard alloys
Biological samples
Issue Date: 1998
Citation: Talanta, 46(4), 1107–1113
Abstract: Cobalt-2-(5-bromo-2-pyridylazo)-5- iethylaminophenol (5-Br-PADAP)- etraphenylborate ion associated complex is quantitatively adsorbed on microcrystalline naphthalene in the pH range 3.5–9.5 from a fairly large volume of the aqueous samples (preconcentration factor -30). After filtration, the solid mass consisting of the cobalt complex and naphthalene was dissolved with 5 ml of dimethylformamide (DMF) and the metal determined by first-derivative spectrophotometry. The cobalt-5-Br-PADAP complex can alternatively be quantitatively retained on ammonium tetraphenylborate-naphthalene adsorbent filled in a column (preconcentration factor 120) in the same pH range and determined similarly. The detection limit is 30 ppb (signal-to-noise ratio=2) and the calibration curve is linear over 0.3–8.0 mg of cobalt in 5 ml of the final DMF solution. Eight replicate determinations of 1.0 mg of cobalt gave a mean peak height of 0.208 (at 611.5 nm) with a relative standard deviation of 1.2%. The sensitivity of the method is 1.04 (dA:dnm) ml mg-1 found from the slope of the calibration curve. The interference of a large number of anions and cations on the determination of cobalt has been studied and the optimized conditions developed were utilized for its trace determination in various standard alloys and biological samples.
URI: http://eprint.iitd.ac.in/dspace/handle/2074/590
Appears in Collections:Chemistry

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