Polarographic determination of the stability constant of the ternary complex formed between cocaine and cobalt thiocyanate |
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Authors: | Dolores Vázquez Belit Garcinuño Jesús Tejedor Luis Deban |
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Affiliation: | Faculty of Sciences, Department of Analytical Chemistry, University of Valladolid, Valladolid, Spain |
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Abstract: | The interactions between cocaine -- Co(II) and thiocyanate (or dimethylglyoxime) have been studied by electrochemical means, assuming the existence of a ternary complex with the stoichiometry [(H2O)3Co(SCN)(C17H21NO4)]+ and the absence of similar ternary species containing dimethylglyoxime. The formation constant of the complex has been evaluated by polarographic titrations because of the irreversibility of electrochemical processes. This relatively small value of 2.37 × 105 is in agreement with the experimental conditions at which Scott's method is typically carried out to detect cocaine in solid samples by reaction with Co(II) thiocyanate. |
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Keywords: | Cocaine ternary complex of cobalt polarographic determination stability constant |
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