Magnesium Oxide R1

Magnesium Oxide R1 MgO = 40.31

Complies with the requirements prescribed for magnesium oxide with the following modifications.

Arsenic (2.4.2, Method A) Maximum 2 ppm.

Dissolve 0.5 g in a mixture of 5 mL of water and 5 mL of hydrochloric acid R1.

Heavy metals (2.4.8) Maximum 10 ppm.

Dissolve 1.0 g in a mixture of 3 mL of water and 7 mL of hydrochloric acid R1. Add 0.05 mL of phenolphthalein solution and concentrated ammonia until a pink colour is obtained. Neutralise the excess of ammonia by the addition of glacial acetic acid. Add 0.5 mL in excess and dilute to 20 mL with water. Filter, if necessary. 12 mL of the solution complies with test A. Prepare the reference solution using a mixture of 5 mL of lead standard solution (1 ppm Pb) and 5 mL of water.

Iron (2.4.9) Maximum 50 ppm.

Dissolve 0.2 g in 6 mL of dilute hydrochloric acid and dilute to 10 mL with water.