A comparative study was carried out for the determination of calcium and magnesium in milk and water melon (food sources of calcium and magnesium). Mixed standard solutions of calcium and magnesium (spike) were added to the samples before digesting with a mixture of concentrated nitric acid and concentrated hydrochloric acid (1:3). The calcium and magnesium content of the digest were determined using flame atomic absorption spectrophotometer (FAAS) and EDTA titration. The percentage recovery for the spikes were as follows: by FAAS determination: the recoveries for the milk samples were within the range (50.0 – 83.3%) for calcium and (48.5 – 83.2%) for magnesium; the recoveries for the watermelon sample were (100%) for calcium and magnesium (49.2 – 83.4%). By EDTA titration: the recoveries for the milk samples were (110.7 -177.8%) for calcium and (89.0 -148.1%) for magnesium; the recoveries for the watermelon samples were (89.0 -133.0%) for calcium and (110.7 – 177.8%) for magnesium. The mean values are: by FAAS determination: for the milk samples: 69.41 ± 0.25 for calcium and 68.03 ± 0.26 for magnesium, for the water melon samples: 100.00 ± 0.00 for calcium and 66.83 ± 0.26. By EDTA titration: for the milk samples: 140.50 ± 0.24 for calcium and 125.30 ± 0.25 for magnesium, for the water melon samples: 111.00 ± 0.26 for calcium and 140.50 ± 0.24 for magnesium. Similarity of the relative standard deviation shows that both methods have similar degree of precision. However, the recoveries by both methods shows better recovery by EDTA titration indicating that the determination of these metals are better with EDTA titration.
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