Jc. Deandrade et al., SPECTROPHOTOMETRIC DETERMINATION OF MO(VI) IN STEEL USING A HOMOGENEOUS TERNARY SOLVENT SYSTEM AFTER SINGLE-PHASE EXTRACTION, Talanta, 47(3), 1998, pp. 719-727
An alternative procedure for the determination of Mo(VI) with thiocyan
ate is proposed. According to this procedure, Mo(VI) is extracted with
alpha-benzoinoxime by single-phase extraction in a water/ethanol/chlo
roform homogeneous ternary solvent system at a nominal pH of 2 and the
n is spectrophotometrically determined, after separation from the matr
ix in a similar solvent mixture. The determination is performed by for
ming a homogeneous phase using the solvent containing the extracted me
tal as one of the components of the reactional solvent system, elimina
ting the time-consuming metal complex destruction step. Under these ex
perimental conditions, the calibration graph is linear up to 8.00 mu g
ml(-1), according to the equation A = 0.005 + 0.143 C-Mo(VI) (r(2) =
0.9999). Using the experimental conditions described, the absorbance r
eadings are stable for periods up to 18 h. The interference of the mos
t common interfering species for this method can be prevented by addin
g Fe2+ and H2PO4- to the solvent system prior to the extraction step.
The accuracy of the proposed method was evaluated by comparing with st
andard samples determined by atomic absorption measurements with backg
round correction. (C) 1998 Elsevier Science B.V. All rights reserved.