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Electrochemical Determination of Adsorption Isotherm of Mordant Red 19 on Mercury and Its Analytical Application for the Indirect Determination of Uranium
Author(s) -
Choi Dongsuk,
Lee Sang Kwon,
Chung Taek Dong,
Kim Hasuck
Publication year - 2000
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/(sici)1521-4109(200005)12:7<477::aid-elan477>3.0.co;2-e
Subject(s) - uranium , adsorption , chemistry , mercury (programming language) , detection limit , adsorptive stripping voltammetry , hanging mercury drop electrode , electrochemistry , langmuir adsorption model , voltammetry , inorganic chemistry , langmuir , trace amounts , antimony , analytical chemistry (journal) , nuclear chemistry , electrode , chromatography , materials science , computer science , metallurgy , programming language , medicine , alternative medicine , pathology
A voltammetric method for the determination of trace level of uranium is described. The method is based on an adsorptive accumulation of the uranium‐Mordant red 19 (MR19, 4‐[(5‐chloro‐2‐hydroxy‐3‐sulfo‐phenyl)azo]‐5‐hydroxy‐3‐methyl‐1‐phenyl‐pyrazole, sodium salt) complex on a hanging mercury drop electrode followed by the reduction of the adsorbed complex. A detection limit of 8.0×10 –11 M uranium can be obtained with a controlled adsorptive accumulation for 10 min. A linear response is obtained from 4.0×10 –8 M to 5.0×10 –6 M concentration of uranium with the relative standard deviation of 3.9 % at 5.0×10 –8 M uranium. The interfacial and redox behavior are characterized by cyclic voltammetry. Chronocoulometry has been used to evaluate the surface coverage vs . the concentration of MR19 in 0.05 M KHP buffer. The surface excess obeys Langmuir isotherm over the concentration range from 1.0×10 –8 M to 1.0×10 –6 M with a saturation limit of 1.08×10 –10 mol/cm 2 , which corresponds to the cross‐sectional area of 154 Å 2 /molecule. The effect of various operational parameters on the stripping response is discussed. Also interferences from other metal ions are examined.