ISO 779:2005 specifies the procedure for the determination of acid-soluble iron by atomic absorption spectrometry or by plasma emission spectrometry.
It is applicable to all kinds of paper, board and pulp.
It specifies a method to determine the acid-soluble part of the incineration residue, i.e. that part of the ignition residue obtained after incineration which is soluble in hydrochloric acid. If the residue is completely soluble, the result obtained by the procedure specified in ISO 779:2005 is taken as the total amount of iron in the sample.