Naslov
Extraction and Complex Formation of Niobium(V) with Xylenol Orange in Presence of 4-Pyridone Derivatives

Autori
Gojmerac Ivšić, Astrid ; Galić, Nives ; Tomišić, Vladislav

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Euroanalysis XIV : Book of Abstracts / - Antverpen, 2007, 818-818

Skup
Euroanalysis XIV

Mjesto i datum
Antwerpen, Belgija, 09.09.2007. - 14.09.2007

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
niobium determination ; xylenol orange ; 4-pyridone derivative ; Spectrophotometry ; Extraction

Sažetak
Xylenol orange (XO) is a suitable reagent for spectrophotometric determination of niobium in a weakly acidic medium.The present study shows that the addition of 4-pyridone derivatives influence on complex formation as well as on the spectroscopic properties of this coloured system. To prevent the formation of niobium(V) hydrolysed species in water tartaric acid was used for preparing niobium solution. The addition of 3-hydroxy-2-methyl-1-phenyl-4-pyridone (HX) increases the sensitivity of Nb-XO reaction. The species formed in presence of HX at pH = 3 by heating has a maximum absorption at 565 nm and molar apsorptivity about 24000. The red coloured complex formed between niobium(V) and xylenol orange (XO) in presence of HX can be extracted by chloroform solution of tetraphenylphosphonium (TPP) chloride. The mechanism of extraction is probably based on the formation of the ion-associated compound formed between the onium cation and mixed Nb(V)-XO-HX anion. The extracted complex in chloroform showed maximum absorbance at 585 nm and obeys Beer`s law in the range 3x10-6 - 3x10-5 mol dm-3. The molar absorptivity is in order of 38500. It is interesting to point out that tantalum does not undergo any colour reaction with xylenol orange. On the base of our study the method for spectrophotometric determination of traces niobium in presence of tantalum can be proposed.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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