Open AccessKinetic Spectrophotometric Determination of Trace Cadmium in Environmental Fresh Water with 5,10,15,20-Tetraphenyl-21H,23Hporphinetetrasulfonic Acid
Author(s) -
Yuya Sasaki,
Naoki Yamamoto,
Yasuhiro Suzuki,
Ikuo Ueta,
Susumu Kawakubo
Publication year - 2015
Publication title -
analytical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 73
eISSN - 1348-2246
pISSN - 0910-6340
DOI - 10.2116/analsci.31.551
Subject(s) - chemistry , cadmium , zinc , detection limit , absorbance , calibration curve , tap water , chelation , nuclear chemistry , kinetic energy , trace amounts , inorganic chemistry , analytical chemistry (journal) , chromatography , medicine , physics , alternative medicine , organic chemistry , quantum mechanics , pathology , environmental engineering , engineering
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.