Validation of the Analysis of Respirable Crystalline Silica (Quartz) in Foams Used with CIP 10-R Samplers

摘要

Sampling the respirable fraction to measure exposure to crystalline silica is most often carriednout using cyclones. However, low flow rates (<4 l min21) and continuing improvement in workplacenhygiene means less and less material is sampled for analysis, resulting in increasednanalytical uncertainty. Use of the CIP 10-R sampler, working at a flow rate of 10 l min21, isnone attempt to solve current analytical difficulties. To check the ability of the analysis of quartznsampled on foams, known amounts of quartz associated with a matrix have been injected intonfoams. The results obtained show that the proposed protocol, with prior acid attack and ashingnof the foams, satisfies the recommendations of EN 482 Standard [CEN. (2006) Workplacenatmospheres—general requirements for the performance of procedures for the measurementsnof chemical agents. Brussels, Belgium: EN 482 Comite´ Europe´en de normalization (CEN).],nnamely an expanded uncertainty of <50% for quartz weights between 0.1 and 0.5 times then8-h exposure limit value and <30% for quartz weights between 0.5 and 2 times the 8-h exposurenlimit value, assuming an exposure limit value equal to 0.1 mg m23. Results obtained shownthat the 101 reflection line allows a quartz quantity of the order of 25 mg to be satisfactorilynmeasured, which corresponds to a 10th of the exposure limit value, assuming an exposure limitnvalue of 0.05 mg m23. In this case, the 100 and 112 reflection lines with expanded uncertaintiesnof u000150% would also probably lead to satisfactory quantification. Particular recommendationsnare also proposed for the preparation of calibration curves to improve the method.