Samples Containing Beryllium

Hydrolytic Stability and Preferred Matrices

• Be has a tendency to hydrolyze in water at a pH of ≥ 4.2. When diluting Be standards they should only be added to pre-acidified water.
• Be(OH)₂ is one of the least soluble Be compounds. It is precipitated as the hydroxide by NH₄OH or the fixed alkalis. In addition, beryllium hydroxide has a tendency to form colloidal suspensions that are difficult to detect visually.
• There are three forms of the hydroxide, namely, the freshly precipitated amorphous form (readily soluble in dilute acid), the a-form produced on standing and the ß-form produced after prolonged heating. Stability constants for the a-form are most readily available.
• The following table shows the improvements in hydrolytic stability of Be with different complexing agents. The pH where precipitation begins is shown for 0.1 M solutions of each complexing agent:

• Be can be mixed with any of the elements, at moderate to high concentrations (< 1 to 1000 µg/mL) but care must be taken to maintain a pH < 2 when nitric acid is used. One of the above complexing agents is needed for solutions with a pH > 2.
• Be has a relatively simple emission spectrum. A popular Be emission line is the 234.861 nm line with a DL of ~0.0003 µg/mL (axial view) because of its relative freedom from spectral interference combined with high sensitivity.

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