Potentiometric microdetermination of cadmium in organic compounds after oxygen flask combustion |
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Authors: | Antonio Campiglio |
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Affiliation: | (1) Dipartimento di Chimica Farmaceutica, Universitá di Pavia, Via Taramelli 12, I-27100 Pavia, Italia |
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Abstract: | The sample is burnt in an oxygen flask and the combustion products are absorbed in lM HNO3. After removal of interfering gases by boiling, the solution is transferred to the titration cell and neutralized with NaOH in the presence of methyl red; Cd(II) is finally titrated potentiometrically in a buffered 50% ethanolic medium with 0.01M sodium diethyldithiocarbamate in 50% ethanol. A silver/sulphide ion-selective electrode and a double junction reference electrode containing a 10% KNO3 solution in 26% ethanol in the outer compartment are used in combination with a Titroprocessor to detect the end point. The results obtained are very accurate and reproducible: the maximum error does not exceed 0.09%, the recovery of cadmium is in the range 99.67 to 99.95% and the rel. standard deviation is 0.05%. The potentiometric titration with diethyldithiocarbamate, which is useful to determine small Cd(II) amounts down to 30g (2g ml–1), as well as the oxygen flask combustion of organic cadmium compounds are discussed. |
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Keywords: | organo-cadmium microdetermination oxygen-flask combustion |
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