Cellulose functionalized with 8-hydroxyquinoline: new method of synthesis and applications as a solid phase extractant in the determination of metal ions by flame atomic absorption spectrometry

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Gurnani, Vibha
Singh, Ajai K
Venkataramani, B
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8-Hydroxyquinoline has been immobilized on cellulose via a moderate size ---NH---CH2---CH2---NH---SO2---C6H4---N=N--- linker and the resulting macromolecular chelator (and intermediates) characterized by infrared spectrometry, cross-polarization magic angle spinning (CPMAS) 13C NMR spectrometry and thermogravimetric analysis (TGA). It has been used for enrichment of Cu(II), Zn(II), Fe(III), Ni(II), Co(II), Cd(II) and Pb(II) prior to their determination by flame atomic absorption spectrometry (FAAS), which are quantitatively sorbed (recoveries>97%) at pH 4.2–6.7, 4.2–7.5, 2.0–3.0, 5.3–6.7, 5.3–6.2, 6.2–9.0 and 4.2–5.3, respectively. The sorption capacity for the seven cations varies from 93.8 to 629.9 μmol g−1. HCl or HNO3 (1 mol dm−3) may be used to desorb all the cations. The optimum flow rate for sorption and desorption has been found to be 2–4 cm3 min−1. The tolerance limits of electrolytes NaCl, NaBr, NaNO3, Na2SO4, Na3PO4 and cations Ca2+ and Mg2+ (added as chloride and sulphate, respectively) in the sorption of all these metal ions are reported. The preconcentration factor is between 90 and 300. Simultaneous sorption of the cations other than iron(III) is possible if their total concentration does not exceed sorption capacity. The present matrix coupled with FAAS has been used to enrich and determine the seven metal ions in river water samples (R.S.D.<7.4%) and water samples having a composition similar to certified water sample SLRS-4 (NRC, Canada) with R.S.D. 2.3%.
8-Hydroxyquinoline, Metal ion, Preconcentration, Flame atomic absorption spectrometer, Chelating cellulose, Enrichment