Up to 1% of As may be present in some alloys
of interest. As it is not separated by the preliminary
group precipitation and reacts with TDTC, it
would cause a positive error. Even 0.1 mg of it
would increase the mass of the Sn-precipitate by 0.7
mg. Hence, it seems advisable to keep it in the
trivalent state and distil off as AsCl3. Ge(IV) is an
interferent [14] of rare occurrence. If present, it can
be removed together with As.