Determination of nanogram amounts of sulphide by release of radioactive iodide.
Two variants of a technique for determination of ng-amounts of sulphide ions in liquid samples are presented. They are based on the replacement of radioactively labelled iodide from silver iodide by sulphide. In the first variant, suitable for small sample volumes, the labelled silver iodide is fixed on a filter paper disc which is then shaken with the solution to be analysed until equilibrium is attained. In the second variant, suitable for sample volumes up to 300 ml, the sample solution is passed through a filter paper disc carrying labelled silver iodide or through a labelled silver iodide precipitate. The amount of sulphide is determined from the activity of the released radioiodide by comparison with standards which have been processed in the same way. The method is applicable to sulphide amounts greater than 5 ng and concentrations greater than 0.2 ppM. The interference by many common accompanying anions and cations has been investigated.
Kriván
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Max-Planck-Institut für Metallforschung, Laboratorium für Reinststoffe, Schwäbisch Gmünd, German Federal Republic.
Pahlke
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Tölg
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