Reliability of the direct ICP-MS analysis of volcanic ash nanoparticles

In the present work, major and trace element concentrations in suspensions of volcanic ash nanoparticles were determined by ICP-MS after either the acid digestion of the suspensions or the direct analysis of these suspensions. The results obtained were compared. Since the acid digestion can be accompanied by an important dilution or can consist in different steps of evaporation and dilution, the determination of some trace element concentrations became limited because of the limit of detection of the analytical instrument. Therefore, analysis after acid digestion of suspensions and direct analysis after acidification of these suspensions were carried out and compared. The concentration of Al, Fe, Y, La, Ce, Pr, Gd, Ho, Cu, Tl and Pb determined by both preparation procedures were in agreement. The values of relative standard deviation are in the range from 1% to 14%. These results prove the reliability of the direct ICP-MS analysis and the possibility of its further application in hyphenated systems for the dimensional and elemental characterisation of natural mineral nanoparticles.