This procedure is essentially the same for Al. The only major difference in the chemical processing is that the quartz sample typically contains a relatively large amount of total Al, so it is not necessary to add Al carrier. Thus, the total number of atoms of stable Al in the sample, here denoted , replaces the number of atoms of the stable nuclide added as carrier. This quantity is:
where is the molar weight of Al (26.982 g mol) and is the mass of Al in the sample (g). The mass of Al in the sample is usually determined by ICP-OES or AA analysis of an aliquot taken immediately after the sample has been dissolved. The Al concentration in quartz, , is then:
where is the measured Al/Al ratio. The uncertainty is:
One determines the process blank for Al measurements in the same way as for Be, as described above. Al is a much less common nuclide in the environment, so generally Al blanks are less important than Be blanks.