Beryllium Measurement by Optical Fluorescence in Samples Contaminated by Strongly Fluorescent Impurities

Abstract

A fluorescence method for determination of beryllium and beryllium oxide particles has been approved as a standard test method by ASTM International and the National Institute for Occupational Safety and Health. The procedure involves dissolution of samples in ammonium bifluoride solution and adding a small aliquot of extract to a basic hydroxybenzoquinoline sulfonate fluorescent dye and measuring itsfluorescence. This method is specific to beryllium and is not affected by the presence of other metals. However, the results from such a method may be compromised by organic fluorescent impurities which have optical characteristics similar to the beryllium-bonded hydroxybenzoquinoline sulfonate. This study demonstrates that such impurities can be effectively removed by activated charcoal without compromising the sensitivity of the method or any other test attributes.

Optical molecular fluorescence determination of ultra-trace beryllium in occupational and environmental samples using highly alkaline conditions

“…5 This interferes with fluorescence measurement and biases the results towards lower amounts of measured beryllium. 29 The yellowness in the solutions may be removed by immediate filtering through GHP hydrophilic polypropylene filters of pore size 0.2 μm or finer; alternatively, it is an option to wait for at least two hours for these metal impurities to settle out before filtering. Solutions were made up with beryllium and ferric chloride hexahydrate (as a source of Fe) in dilute NH 4 HF 2 (1% and 3% NH 4 HF 2 in water) and then mixed with the appropriate dye solution (lysine-free or with lysine) using 5× and 20× dilution.…”