Automatic determination of calcium and magnesium in water.
Magnesium and calcium may each be determined in water by an automatic spectrophotometric method. At 571 nm with an excess of Eriochrome Black T as metallochromic agent, the variation m absorbance is proportional to the magnesium concentration regardless of the calcium concentration. By addition of MgEDTA to displace the calcium from its CaEBT complex, this element may be determined at the same wavelength. For 3-25 ppm of magnesium and 5-40 ppm calcium, the standard deviation was about 4%. The apparatus is described.
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Istituto Chimica Analitica Universita' di Bari Italy.
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Papoff
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