engleski

Monoethyl-a-anilinobenzylphosphonic acid as a potential analytical reagent

Monoethyl-a-anilinobenzylphosphonic acid (HEt) is one among previously prepared similar compounds. It is soluble in water and in different organic solvents. Its proper-ties in solution indicate the possibility of its application as an analytical reagent. The reagent is applied to study the possibilities of spectrophotometric and spectro-fluorometric determination of tungsten(VI) and molybdenum(VI) in aqueous solutions. Absorption maxima of HEt appear at 243 nm and 290 nm, with molar absorbtivity val-ues of 1.32x104 l mol-1 cm-1 and 1.34x103 l mol-1 cm-1, respectively. Both metal ions form complex species with HEt, effecting the appearance of absorbance spectra. Measuring UV spectra of metal(VI)-HEt systems against the blank solution results in the appearance of new maxima, whereas the position of the absorbance maximum at 290 nm remains unchanged, and the one at 243 nm changes it's characteristics. Tung-sten(VI)-HEt solutions absorb at 276 nm having the molar apsorptivity 2.33x103 l mol-1 cm-1, whereas species formed in the molybdenum(VI)-HEt systems absorb at 260 nm with molar apsorptivity value of 1.90x103 l mol-1 cm-1. The conditions for the spectro-photometric determination depend upon concentrations of all components, as well as upon the acidity of measured systems. Differences in relative fluorescence intensities, comparing the reagent fluorescence spectra with those of metal(VI)-HEt systems, indicate the existence of metal complex species and the possibility of their spectro-fluorometric study. Monoethyl-a-anilinobenzylphosphonic acid, although previously not applied as an analytical reagent, reacts with metal ions opening therewith broad possibilities for metal ions determination in aqeous solutions.

analytical reagent ; monoethyl-a-anilinobenzylphosphonic acid

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