title: Spectrophotometric determination of thorium in standard samples and monazite sands based on the floated complex of thorium with N-hydroxy-N,N'-diphenylbenzamidine and thorin.
abstract: A selective and sensitive spectrophotometric method for the determination of Th(IV) has been based on the reaction with thorin and subsequent extraction of the red-orange coloured complex with N-hydroxy-N,N'-diphenylbenzamidine (HDPBA) in benzene as floated complex at pH 2.2. The complex in ethanol exhibits a maximum absorbance at 495 nm, with a molar absorptivity of 6.0x10(4) l mol(-1) cm(-1), with a Sandell's sensitivity of 3.9x10(-3) microg cm(-2). The method follows Beer's law up to 3.0 microg Th(IV) ml(-1). None of the common cations and anions tested interfere. The detection limit of the method is 0.04 microg Th(IV) ml(-1), the RSD (n=10) is 1.4%. The method has been successfully employed for the determination of thorium in various standard and monazite samples.
authors.affiliation: School of Studies in Chemistry, Pt. Ravishankar Shukla University, 492010, Raipur, M.P., India.
authors.forename: N
authors.initials: N
authors.lastname: Nashine
authors.forename: M K
authors.initials: MK
authors.lastname: Deb
authors.forename: R K
authors.initials: RK
authors.lastname: Mishra