Re-assessment of chelating ion-exchange resins for trace metal analysis of sea water

Electrothermal atomic absorption spectrometric determination of cadmium in environmental samples with niobium wire preconcentration method

“…The pH in the reaction is a very important factor because it regulates the release of free Cd species from the forms which were chemically bound to organic, colloidal, and mineral components in natural water samples [26,27]. The influence of the pH on the adsorption of Cd onto niobium wire was evaluated in the case of a solution with 1.0 ng Cd mL À1 .…”

“…Moreover, it would be considered that the physical adsorption and the interaction between the element cadmium and the niobium wire surface might also occur as the preconcentration mechanism. From the information in the literature [7][8][9][10][11][12][13][14][15][16][17][18][19][25][26][27][28][29], it is not clear which process is predominant for the adsorption of cadmium on the niobium wire. These processes are still being examined.…”

Determination of chromium in river waters by electrothermal atomic absorption spectrometry with preconcentration on a tantalum wire

“…Hot acid digestion is the only reliable method for converting the total metal to a simple ionic form. However at a pH below 3.5 all metals are released [16] with the exception of the most strongly bound of the organic, colloidal, and mineral components. Thus, the ability to pre-concentrate below this pH value is vital in achieving data representative of total metal concentrations.…”

“…The influence of pH is very important because it regulates the release of free ions of chromium from chemically bound forms in natural water samples [12,15,16] and our method pre-concentrates the free ionic species of chromium. Hot acid digestion is the only reliable method for converting the total metal to a simple ionic form.…”

Comparison study of copper ion adsorption on chitosan, Dowex A-1, and Zerolit 225

“…resin for collection of trace metal is reasonably Although a considerable number of articles have well understood. [2][3][4] The analytical application of so far been published concerning the adsorption of the chelating ion exchange resin has become inmetal ions on chitosan, there have been only a few articles concerning the comparison adsorption behavior between chitosan and commercial chelating and Zerolit 225 as a function of concentration using atomic absorption spectrophotometer. For copper ion adsorption on Dowex A-1, stock solutions conatomic absorption spectrometry.…”