Novel potentiometric membrane sensor for the determination of trace amounts of chromium(III) ions.
A plasticized Cr3+ ion sensor by incorporating 2,3,8,9-tetraphenyl-1,4,7,10-tetraazacyclododeca-1,3,7,9-tetraene (TTCT) ionophore exhibits a good potentiometric response for Cr3+ over a wide concentration range (1.0 x 10(-6)-1.0 x 10(-1) M) with a slope of 19.5 mV per decade. The sensor response is stable for at least three months. Good selectivity for Cr3+ in comparison with alkali, alkaline earth, transition and heavy metal ions, and minimal interference are caused by Li+, Na+, K+, Co2+, Hg2+, Ca2+, Pb2+ and Zn2+ ions, which are known to interfere with other chromium membrane sensors. The TTCT-based electrode shows a fast response time (15 s), and can be used in aqueous solutions of pH 3-5.5. The proposed sensor was used for the potentiometric titration of Cr3+ with EDTA and for a direct potentiometric determination of Cr3+ content in environmental samples.
Ganjali
Mohammad Reza
MR
Department of Chemistry, Faculty of Science, Tehran University, Tehran, Iran. ganjali@Khayam.ut.ac.ir
Mizani
Farhang
F
Salavati-Niasari
Masoud
M
Javanbakht
Mehran
M
D002857:Chromium / Q000032:analysis*; D004785:Environmental Pollutants / Q000032:analysis; D006573:Heterocyclic Compounds, 1-Ring / Q000737:chemistry*; D017736:Ion-Selective Electrodes / Q000592:standards*; D007476:Ionophores / Q000737:chemistry; D008670:Metals / Q000032:analysis; D010968:Plasticizers / Q000737:chemistry; D012016:Reference Values; D012680:Sensitivity and Specificity
C475892:2,3,8,9-tetraphenyl-1,4,7,10-tetraazacyclododeca-1,3,7,9-tetraene; D004785:Environmental Pollutants; D006573:Heterocyclic Compounds, 1-Ring; D007476:Ionophores; D008670:Metals; D010968:Plasticizers; D002857:Chromium