Determination of magnesium and calcium in water with ion-selective electrodes
1989; Elsevier BV; Volume: 218; Linguagem: Inglês
10.1016/s0003-2670(00)80281-0
ISSN1873-4324
AutoresMagdalena Maj‐Żurawska, Marizel Rouilly, Werner E. Morf, W. Simon,
Tópico(s)Electrochemical Analysis and Applications
ResumoThe sum of the concentrations of calcium and magnesium in water samples can be determined directly with a neutral carrier-based Mg2+/Ca2+-selective electrode (divalent ion-selective electrode), without addition of any auxiliary complexing agent such as acetylacetone. This approach works well, even in situations where calcium-selective electrodes do not detect the second inflection point because the calcium/magnesium concentration ratio is too high ([Ca2+]:[Mg2+] ⪢5:1) or the sodium concentration is high. With high levels of acetylacetone (0.1 M) the divalent ion- selective electrode can also be used for calcium determinations. For such measurements, however, the standard deviations obtained with the calcium-selective electrode are smaller. A theoretical description of titration curves corroborates these findings.
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