Quinoline-8-ol modified cellulose as solid phase extractant (SPE) for preconcentrative separation and determination of thorium(IV)

Abstract

Abstract Cellulose has been functionalized by coupling with 5-chloro-quinoline-8-ol in the presence of alkali. The resulting polymer material has been characterized by IR spectra and has been used for preconcentrating thorium prior to its determination by spectrophotometry. The optimum pH value for quantitative extraction is 5.0–7.0 and can be eluted with 5cm3 of 1mol dm-3 of HCl. The retention capacity of the quinoline-8-ol modified cellulose is 20.0mg g-1. The effect of various cations, anions and neutral electrolytes on the preconcentration of thorium in conjunction with the determination procedure has been studied and we have found that none of interferents including uranium (up to 10 fold amounts) interfere. The enrichment factor for preconcentration of thorium was found to be 200. Ten replicate determinations of 10μg of thorium (IV) present in 1dm3 of sample gave a mean absorbance of 0.084 with a relative standard deviation 1.52. The detection limit (corresponding to three times the standard deviation of the blank) was found to be 2μg dm-3. The thorium content of mixed rare earth chloride solution obtained from Indian Rare Earths Limited (IRE), India was estimated by using quinoline-8-ol immobilized cellulose for preconcentration and subsequent determination by spectrophotometry.