title: A dispersive liquid-liquid microextraction procedure for determination of boron in water after ultrasound-assisted conversion to tetrafluoroborate.
abstract: A novel, simple and green procedure is presented for the determination of boron. The method is based on ultrasound-assisted conversion of boron to tetrafluoroborate anion and the formation of an ion pair between BF(4)(-) and Astra Phloxine reagent (R), followed by dispersive liquid-liquid microextraction of the ion pair formed and subsequent UV-vis spectrophotometric detection. The conversion of boron to tetrafluoroborate anion is performed in an acidic medium of 0.9 mol L(-1) H(2)SO(4) in the presence of 0.1 mol L(-1)F(-) by means of 10 min of ultrasonication. The extraction of the ion pair formed between BF(4)(-) and R (1×10(-4)mol L(-1)R) is carried out by dispersive liquid-liquid microextraction using 0.5 mL of amyl acetate (as extraction solvent), tetrachloromethane (as auxiliary solvent) and acetonitrile (as dispersive solvent) in a ratio of 1:1:2. The absorbance of the coloured extracts obeys Beer's law in the range 0.22-18.7 mg L(-1) of B(III) at 553 nm wavelength. The limit of detection calculated from a blank test (n=10) based on 3s is 0.015 mg L(-1) of B(III). The method was applied to the determination of boron in mineral waters.
authors.affiliation: Department of Analytical Chemistry, University of P.J. Šafárik, SK-04154 Košice, Slovakia.
authors.forename: Lenka
authors.initials: L
authors.lastname: Rusnáková
authors.forename: Vasil
authors.initials: V
authors.lastname: Andruch
authors.forename: Ioseph S
authors.initials: IS
authors.lastname: Balogh
authors.forename: Jana
authors.initials: J
authors.lastname: Skrlíková
mesh_terms: D001881:Borates; D001888:Boric Acids / Q000032:analysis / Q000138:chemical synthesis*; D001895:Boron / Q000032:analysis* / Q000737:chemistry; D003116:Color; D055772:Green Chemistry Technology; D057230:Limit of Detection; D008900:Mineral Waters / Q000032:analysis; D013057:Spectrum Analysis; D014465:Ultrasonics; D014867:Water
chemical_list: D001881:Borates; D001888:Boric Acids; D008900:Mineral Waters; D014867:Water; C098759:fluoroboric acid; D001895:Boron