ABSTRACT
The applicability of a dropping indium amalgam electrode for the determination of metal ions in the presence of large concentrations of halides by means of amperometric complex-formation titrations using normal pulse polarography has been investigated. Titrations appear to be possible in the presence of 4M potassium iodide, 1M potassium bromide and 1M potassium chloride.
ABSTRACT
The behaviour of the dropping lead amalgam electrode has been studied. Calculated and experimental current-voltage curves have been compared and an explanation has been given for the observed differences. Selective determination of metal ions appears to be possible in the presence of saturated chloride, 1M bromide and 10(-2)M iodide by means of amperometric complex-formation titrations using normal pulse polarography with the dropping lead amalgam electrode.
ABSTRACT
The use of the dropping bismuth amalgam electrode has been investigated for the selective determination of metal ions in the presence of large concentrations of halides by means of amperometric complex-formation titrations, using normal pulse polarography. Concentrations of metal ions down to 3 x 10(-7)M have been determined with adequate accuracy in the presence of about 0.1M chloride or 0.01M bromide. Calculated and experimental current-voltage curves have been compared and found to be in reasonable agreement.
ABSTRACT
Selective determinations of several metal ions by means of amperometric complex-formation titrations employing normal pulse polarography with a DME appear to be possible. Concentrations down to 3 x 10(-7)M have been determined with adequate accuracy. In alkaline medium deaeration is necessary; in acidic medium it can be omitted.
ABSTRACT
The interference of halides with complexometric titrations, indicated by means of the anodic wave of the ligand at a rotating mercury electrode, has been studied theoretically. The effect of halides strongly depends on the pH of the solution. In alkaline solutions there appears to be no interference by chloride at all. A critical value for the halide concentration can easily be found for any medium. The theoretical predictions have been verified experimentally.
ABSTRACT
Zinc forms fluorescent complexes with 8-hydroxyquinoline-5-sulphonic acid (HQS) in the pH region 7-10. The stability of these complexes is such that two different titration procedures are possible: the titration of zinc with HQS and the titration of zinc with EDTA in the presence of HQS. For both procedures the choice of the titration conditions is described. Also two separation procedures for zinc are described, especially suitable in connection with the EDTA titration. The practical results show that zinc in concentrations larger than 10(-6)M (0.05 mug/ml) can be titrated with good precision.
ABSTRACT
Formulae for the fluorescence signal are derived which take into account some factors hitherto neglected. From these formulae conditions are deduced, for which a linear relationship exists between the concentration of the fluorescent components and the intensity of the fluorescence. In some cases of practical interest the fulfilment of these conditions cause too low a sensitivity. For such cases a method of optimization is outlined, by means of which the conditions are found which lead to the least deviation from linearity at the required sensitivity.
ABSTRACT
Thorium has been determined in the microgram range by complexometric titration with EDTA. The end-point was detected by following the anodic wave of EDTA at a rotating mercury electrode. It has been shown that thorium can be titrated in the presence of large amounts of other metals. Following electrolysis at a mercury pool electrode the titration is selective for thorium.
ABSTRACT
Copper has been determined in the submicrogram range by means of a eomplexometric titration with triethylenetetramine (TRIEN), the end-point being detected by following the anodic wave of the chelating agent at a rotating mercury electrode. The influence of the presence of other metals has been investigated both from the theoretical and the experimental point of view. Because of its higher selectivity TRIEN is preferred to other reagents of the EDTA group. The results show that copper can be determined in the presence of large amounts of most other metals.
ABSTRACT
Alkaline earth metals were determined in microgram quantities by complexometric titration with EDTA, EGTA and DTPA. The end-point was detected by following the anodic wave of the chelating agent at the rotating mercury electrode. All the alkaline earths can be titrated at the microgram level with reasonable accuracy, and calcium may be titrated with EGTA in the presence of a 1000-fold excess of magnesium.
ABSTRACT
The amperometric titration of cations with chelating agents can be extended to the microgram range by using a rotating mercury anode.
