engleski

Analysis of Titration Curves of Lake Tjeukemeer Water with Cu(II). Identification of the Formation of More than Two Groups of Different Complexes.

The results for direct titration of Lake Tjeukemeer water with Cu(II) are interpreted by using both van den Berg-Ružić and Scatchard plots. The use of a new method for correction of asymptote at higher additions of metal proposed by Ružić and Pečar has been illustrated with these titration data. The analysis of reduced titration data obtained bz extraction of equation for weaker complexes from the original titration data has been proved as a very powerful method by which the accuracy of determining complexation parameters for higher energy binding sites can be checked. The following stability constants (K_i) and complexing capacities (L_Ti) are reported: K_1=1.661*10^4 dm^3mol^-1 L_T1=7.978*10^-5 mol dm^-3 K_2=3.014*10^5 dm^3mol^-1 L_T2=1.278*10^-5 mol dm^-3 K_3=1.588*10^7 dm^3mol^-1 L_T3=5.432*10^-6 mol dm^-3 K_4=6.432*10^8 dm^3mol^-1 L_T4=5.996*10^-7 mol dm^-3 High concentration of organic matter in the Lake made possible direct titration with Cu(II) in a wide range of concentrations, so that four different binding strengths were able to be detected from the titration data.

trace metals; complexation; titration curves; lake water

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