Extraction and simultaneous spectrophotometric determination of vanadium(IV) and vanadium(V) in admixture with 2-hydroxyacetophenone oxime

Abstract

Vanadium(lV) and vanadium(V) in the presence of 2-hydroxyacetophenone oxime were extracted quantitatively into chloroform in the pH ranges 3.6-4.5 and 2.7-4.1, respectively. The organic layer showed absorbance maxima at 345 and 350 nm for V I V and VV, respectively. Studies of the behaviour of V'V were also carried out a t a wavelength of 350 nm. Vanadium(V) absorbed considerably beyond 380 nm whereas Viv had negligible absorbance in this region. The absorbance of the organic layer, for both VIV and VV, was unaltered, even after 4 d. The composition of the complexes formed was established to be 1 : 2 (metal : ligand) by Job's method. Interference studies were carried out for both V i V and VV and methods are suggested for eliminating interference by foreign ions. Both VIV and VV are extracted quantitatively at pH 4; this extraction was exploited successfully for the simultaneous determination of VIV in the range 1-3 pg ml-1 and VV in the range 1-6 pg ml-1 by measuring the absorbances at 350 and 400 nm, respectively.

Determination of trace levels of dissolved vanadium in seawater by use of synthetic complexing agents and inductively coupled plasma-atomic emission spectroscopy (ICP-AES)

“…As shown in Fig. 1, vanadium complexation by 8-HQ is very efficient (~100% in the wide pH range 3-8) so this reagent can be used for vanadium speciation studies at natural pH (7)(8) without any treatment.…”

“…Many such techniques have been proposed, including solvent extraction, precipitation, co-precipitation, and ion exchange. Solvent extraction [7], and co-precipitation [8,9] have been commonly used for the pretreatment of vanadium, but they are laborious and apt to carry a risk of contamination and possibility of interference effects.…”

RETRACTED: Spectrophotometric determination of V(V) in environmental, biological, pharmaceutical and alloy samples by novel oxidative coupling reactions

“…Recently, few authors introduced various reagents for spectrophotometric determination of vanadium in various samples such as 2-(2-quinolylazo)-5-diethylaminophenol [10], varamine blue [11], eriochrome cryamine R [12], 2-benzylacetate [13], pyrogallol [14], 2-hydroxyacetophenone oxime [15], 4-(2-pyridylazo) resorcinol [16], tannic acid [17], 2-(5-chloro-2-pyridylazo)-5-dimethylaminophenol [18] N,N -bis(2-hydroxyl-3-sulfopropyl)-tolidine [19] and 2-(8-quinolylazo)-5-dimethylaminophenol [3]. The above reported reagents were suffers from poor selectivity, interference of large number of metal ions, require specific protonic solvent for the extraction of color species and few other are require activators for catalytic photometric determination of vanadium.…”

Selective determination of total vanadium in water samples by cloud point extraction of its ternary complex

“…samples are liquid-liquid extraction (LLE) [5][6][7], solid-phase extraction (SPE) [8][9][10][11][12][13], precipitation or coprecipitation [14][15][16][17], and ion exchange [18][19][20]. The separation and preconcentration of metal ions, after formation of their sparingly soluble aqueous complexes based on cloud point extraction (CPE) have been largely employed in analytical chemistry [21].…”