Extraction-spectrophotometric determination of vanadium with 3,5-dinitrocatechol and Brilliant Green

Z. Marczenko , Ryszard Lobinski (1, 2)

1 LCABIE - Laboratoire de Chimie Analytique Bio-Inorganique et Environnement
2 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

The formation and extraction of the ion-associates of the vanadium(V)-3,5-dinitrocatechol (DNC) anionic chelate complex with various basic dyes have been studied and a new sensitive extraction-spectrophotometric method for the determination of vanadium based on the system V(V)-DNC-Brilliant Green has been developed. Beer's law is obeyed up to a vanadium concentration of 0.3 μg/ml and the molar absorptivity is 1.7 × 1O5 l.mole-1. cm-1 at 630 nm. The molar ratios of the components and the form of the vanadium(V) cation in the extracted compound have been determined, and the formula [VO(OH)(DNC)2- 2][BG+]2 is proposed. Titanium, molybdenum, tungsten, EDTA and thiocyanate interfere seriously. The method becomes specific after a preliminary separation of vanadium by its extraction as the BPHA complex from H2SO4-HF medium, and is 40 times more sensitive than the spectrophotometric BPHA method. The proposed method has been applied to determination of traces of vanadium (about 10-5%) in alums. © 1988.

Domaines: Chimie analytique

Z. Marczenko, Ryszard Lobinski. Extraction-spectrophotometric determination of vanadium with 3,5-dinitrocatechol and Brilliant Green. Talanta, 1988, 35 (12), pp.1001--1004. ⟨10.1016/0039-9140(88)80236-4⟩. ⟨hal-01559741⟩