For ICP-AES or FLAA analyses, hydrochloric acid (HCl) is added to the initial
digestate and the sample is refluxed. In an optional step to increase the solubility of some metals
(see Section 7.3.1: NOTE), this digestate is filtered and the filter paper and residues are rinsed, first with hot HCl and then hot reagent water. Filter paper and residue are returned to the digestion flask,
refluxed with additional HCl and then filtered again. The digestate is then diluted to a final volume
of 100 mL.