title: Reaction of mercury(II) and xylenol orange-I Effect of the buffering media.
abstract: The influence of the buffering medium on the reaction of Hg(II) with Xylenol Orange has been studied. Amine-type compounds are complexed by Hg(II)/Xylenol Orange with a sharp hyperchromic effect on the reagent itself, at 590 nm, but complex formation of Hg(II)/Xylenol Orange in non-amine-type buffer, such as citric acid-phosphate, gives a hypochromic effect on Xylenol Orange at 580 nm. Hg(II) is determined at pH 7.5 in two ranges of concentration, 2-9 ppm in citrate buffer, measured at 580 nm ( = 2.50 x 10(4)), and 6-11 ppm in hexamine buffer, at 590 nm ( = 4.18 x 10(4)).
authors.affiliation: Departamento de Química Analítica, Facultad de Ciencias de la Universidad de Madrid, and C.S.I.C., Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Cabrera-Martín
authors.forename: J L
authors.initials: JL
authors.lastname: Peral-Fernández
authors.forename: S
authors.initials: S
authors.lastname: Vicente-Péez
authors.forename: F
authors.initials: F
authors.lastname: Burriel-Martí