Solvent Extraction, Preconcentration and Determination of Thorium with Monoaza 18-Crown-6 Derivative

Abstract

A solvent extraction separation, preconcentration and determination of thorium with a new crown, 2-ethyl-N-benzyl-4,7,10,13,16-pentaoxa-1-azacyclooctadecane (MACE), is described in the study. The amount of thorium in the aqueous phase and organic phase was determined by Inductively Coupled Plasma-Optical Emission Spectroscopy and Ultraviolet-Visible, respectively. Thorium loaded organic phase was quantitatively stripped in a stage by using 1.0 M <TEX>$HNO_3$</TEX>. Thorium was effectively extracted with MACE in the pH range of 6-7 to produce a 3:2 complex ratio in the chloroform. A highly sensitive and rapid spectrophotometric method was described for determination of trace amounts of thorium with MACE. The effective molar absorption coefficient at 281 nm is <TEX>$1.98{\times}10^3\;mol^{-1}cm^{-1}$</TEX>, and the system complies with Beer's law in the range from 0.464 to 2.32 <TEX>${\mu}gm\;L^{-1}$</TEX> of thorium. Thorium was also determined in standard and environmental samples.