Paragraph 4 REAGENTS

Hydrochloric acid solution, about 6 M

4.1

See Method 25d (4.1).

Hydrochloric acid solution, about 0.5 M

4.2

See Method 25d (4.2).

4.3

Hydrogen peroxide solution (30% H₂O, ρ = 1.11 g/ml), free from trace elements.

Copper calibration solutions

4.4

Copper stock solution (1000 μg/ml)

4.4.1

In a 250 ml beaker, weigh to the nearest 0.1 mg, 1 g of copper, add 25 ml of 6 M hydrochloric acid (4.1), add 5 ml hydrogen peroxide solution (4.3) and heat on a hot plate until the copper is completely dissolved. Transfer quantitatively to a 1 litre volumetric flask. Make up to volume with water and mix thoroughly.

Copper working solution (100 μg/ml)

4.4.2

Place 20 ml of the stock solution (4.4.1) in a 200 ml volumetric flask. Make up to volume with 0.5 M hydrochloric acid solution (4.2) and mix thoroughly.