Sampling and analytical methods to characterize Beryllium aerosols produced in occupational settings

To identify traces of airborne beryllium in workplaces sampled on a support, the ICP-MS analysis method was compared to the most sensitive current methods (electro-thermal atomic absorption spectrometry [ETAAS], molecular fluorescence). A laboratory-based approach was used to determine the limits of quantification for the various instruments in a range of matrices representative of the sampling and analysis methods used for beryllium to identify those best adapted to detecting low amounts of beryllium and characterizing aerosols. The solutions used to recover particles from the sampling supports and the aerosols themselves have a direct impact on several parameters of the plasma in the ICP. Thus, these effects vary depending on the matrix itself, on the element analyzed and on the analytical conditions. These effects cannot be completely corrected using an internal standard, therefore matrix reconstitution is recommended.<br/>
The limits of quantification measured in these matrices were generally below 10 ng of beryllium. Results were equivalent or better with the ETAAS technique than with ICP-MS. The best sensitivities were obtained with mixed cellulose ester membranes (MCE), whatever the analysis technique employed. The method developed was validated for assay of beryllium oxide through an international inter-laboratory test. In addition, a protocol combining digestion and ICP-MS assay was developed and validated for two types of impactor. This makes it possible to analyse the chemical composition of an aerosol as a function of its size fraction.<br/>
The aerosol sampling method involving cellulose supports and ICP-MS or ETAAS analysis appears appropriate for the detection of small quantities of beryllium in line with requirements if the 8h-TWA is reduced to 0.05 g.m-3. However, for a more significant reduction, an alternative would be to use an individual sampling device with a flow-rate of more than 2 L.min-1 to increase the amount of aerosol sampled over the same time period.