IMPACT OF SAMPLE QUANTITY AND ABSORBANCE LEVEL ON PARTICLE SIZE ANALYSIS BY LASER DIFFRACTION RESULTS

This study aimed to investigate the impact of sample quantity and absorbance levels on the repeatability of results and to evaluate the suitability of the method for exhaust gases with low dust concentrations. In the research use was made of the ANALYSETTE 22 NanoTec laser particle size analyser with wet dispersion. Water was used as the dispersing agent. The study utilised Fritsch Standard F500 reference dust, with a particle size range of 0.5–50 m, and two dust samples collected from industrial installations. Variations in the results were observed depending on the sample mass introduced into the analyser and the resulting absorbance levels. For the reference dust, repeatable results, consistent with the manufacturer’s specifications, were obtained with absorbance levels of 5–20%. Similarly, the most reproducible results for real dust samples were obtained at comparable absorbance levels. The study emphasized the lack of repeatability at absorbance levels below 5%, which may be attributed to the insufficient amount of dust analysed. It seems necessary to develop an alternative method for collecting dust samples from exhaust gases to avoid relying on dust recovery from filtration materials.