| Sumario: | Sampling the respirable fraction to measure exposure to crystalline silica is most often carried out using cyclones. However, low flow rates (<4 l min−1) and continuing improvement in workplace hygiene means less and less material is sampled for analysis, resulting in increased analytical uncertainty. Use of the CIP 10-R sampler, working at a flow rate of 10 l min−1, is one attempt to solve current analytical difficulties. To check the ability of the analysis of quartz sampled on foams, known amounts of quartz associated with a matrix have been injected into foams. The results obtained show that the proposed protocol, with prior acid attack and ashing of the foams, satisfies the recommendations of EN 482 Standard [CEN. (2006) Workplace atmospheres—general requirements for the performance of procedures for the measurements of chemical agents. Brussels, Belgium: EN 482 Comité Européen de normalization (CEN).], namely an expanded uncertainty of <50% for quartz weights between 0.1 and 0.5 times the 8-h exposure limit value and <30% for quartz weights between 0.5 and 2 times the 8-h exposure limit value, assuming an exposure limit value equal to 0.1 mg m−3. Results obtained show that the 101 reflection line allows a quartz quantity of the order of 25 μg to be satisfactorily measured, which corresponds to a 10th of the exposure limit value, assuming an exposure limit value of 0.05 mg m−3. In this case, the 100 and 112 reflection lines with expanded uncertainties of ∼50% would also probably lead to satisfactory quantification. Particular recommendations are also proposed for the preparation of calibration curves to improve the method.
|
|---|