title: Catalytic flow-injection determination of copper at nanogram levels by using color formation of N-phenyl-p-phenylenediamine with m-phenylenediamine in the presence of pyridine and ammonia as activators.
abstract: A spectrophotometric flow-injection method for determining copper(II) has been developed. It is based on the catalytic effect of copper(II) on the oxidative coupling of N-phenyl-p-phenylenediamine with m-phenylenediamine in the presence of hydrogen peroxide. Pyridine and ammonia as activators increased the absorbance for the copper(II)-catalyzed coloration, and the dye formed was stabilized by adding a non-ionic surfactant. The working range of the method was 0.1-2.0 ng ml(-1) of cooper(II) with a relative standard deviation 2.4% at a sampling rate of 30 h(-1). Interference from iron(III) was effectively suppressed by citric acid. Copper in natural water samples can be determined easily.
authors.affiliation: Chemical Institute, Faculty of Education, Tottori University, Koyama-cho, Tottori 680, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nakano
authors.forename: K
authors.initials: K
authors.lastname: Nakaso
authors.forename: K
authors.initials: K
authors.lastname: Noguchi
authors.forename: T
authors.initials: T
authors.lastname: Kawashima