title: Separation and determination of vanadium in fertiliser by capillary electrophoresis with a light-emitting diode detector.
abstract: A method has been developed for determination of vanadium, as an anionic ternary complex of vanadium(V) with 4-(2-pyridylazo) resorcinol (PAR) and hydrogen peroxide, after separation by capillary electrophoresis (CE). The optimum conditions for the formation of the ternary complex were acetate buffer (3 mmol L(-1)) at pH 6 containing 0.15 mmol L(-1) PAR and 7.1 mmol L(-1) H(2)O(2). The CE separation was conducted using 15 mmol L(-1) acetate buffer at pH 6 as the background electrolyte; the separation potential was -30 kV and the injection time 100 s. The vanadium complex was detected photometrically at 568 nm, by use of a light-emitting diode (LED); the detection limit was 19 ppb. The method was applied to the analysis of vanadium in fertilisers. Clean-up of the digested fertiliser sample, with Sep-Pak C(18) coated with tetrabutylammonium hydroxide, before analysis was used to remove matrix ions which otherwise caused electrophoretic de-stacking. Vanadium levels found in the fertiliser samples by use of the CE method were found to be comparable with results obtained by HPLC and ICP-MS.
authors.affiliation: Department of Chemistry, Faculty of Science and Technology, Thammasat University, Rangsit, Pathumthani, 12121, Thailand.
authors.forename: Narumol
authors.initials: N
authors.lastname: Vachirapatama
authors.forename: Miroslav
authors.initials: M
authors.lastname: Macka
authors.forename: Paul R
authors.initials: PR
authors.lastname: Haddad