Question

2+ EDTA is often used to preserve blood samples because it can complex with Ca which is necessary for clotting. The typical concentration of Ca2 in blood is 1.1 x 10° M and a typical concentration of 4 x 10 M Na2H2EDTA is added. The pH of blood is 7.2 and for this pH, the EDTA alpha fractions are 2 x 1010, 3 x 10, 0.12, 0.88 and 8.1 x 10-4 for α0, α1, α2, α3 and α4, respectively. The formation constant for CaY2 is 4.9 x 1010 a) What is the dominant form of EDTA in the blood? b) What is the final concentration of Ca2*, Y*, CaY2, EDTA and HY3 in 2 mL of a blood sample?

Answer 1

blnod 2+ -0 CEDTA CEDTA 4X10 = 13.6×32,7 640-32-X163

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