title: Kinetic Spectrophotometric Determination of Trace Cadmium in Environmental Fresh Water with 5,10,15,20-Tetraphenyl-21H,23H-porphinetetrasulfonic Acid.
abstract: Cadmium-catalyzed complexation of zinc with 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid (TPPS) was monitored spectrophotometrically. A kinetic parameter for the determination was obtained under kinetic consideration. Absorbance of zinc-TPPS at a fixed reaction time was proportional to the concentration of cadmium at pH 8 and 25°C. Tolerable concentration of interfering ions were 200, 200, 2000, 50, 500 and 1 μg L(-1) for Mg(II), Al(III), Ca(II), Fe(III), Zn(II) and Hg(II), respectively, in the determination of 20 μg L(-1) of cadmium, indicating Ca(II) and Mg(II) interferes with the analysis of natural fresh water. Such interference became tolerable at 5 mg L(-1) by the addition of an excess Ca(II) (50 mg L(-1)) in the reacting solution of sample and cadmium standards. A calibration curve of Cd(II) was linear up to 100 μg L(-1) with a detection limit of 2 μg L(-1). The reliability of the proposed method was confirmed by the recovery test of cadmium spiked into tap, river and reservoir water samples.
authors.affiliation: Graduate School, Department of Interdisciplinary Research, University of Yamanashi.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Natsuki
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Yasutada
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Ikuo
authors.initials: I
authors.lastname: Ueta
authors.forename: Susumu
authors.initials: S
authors.lastname: Kawakubo
mesh_terms: D001060:Aporphines / Q000737:chemistry*; D002104:Cadmium / Q000032:analysis* / Q000737:chemistry; D005618:Fresh Water / Q000737:chemistry*; D007700:Kinetics; D057230:Limit of Detection; D045483:Rivers / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods*; D013451:Sulfonic Acids / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D015032:Zinc / Q000737:chemistry
chemical_list: C000605737:5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic Acid; D001060:Aporphines; D013451:Sulfonic Acids; D014874:Water Pollutants, Chemical; D002104:Cadmium; D014867:Water; D015032:Zinc