Substoichiometric neutron-activation determination of gallium: extraction from HCl with tri-n-octylphosphine oxide in cyclohexane

A highly precise method for the determination of traces of gallium by neutron activation is described. Conditions for the extraction of gallium are reported and general requirements for substoichiometric isolation of cations from HCl with neutral donors are discussed. The mean of determinations of gallium at concentrations of 40 ng ml in a solution prepared by dissolving a standard reference aluminium alloy was 213.9 +/- 1.3 ng. The relative standard deviation and the total error of the method (based on the SRM value) were 0.7 and 10.5% respectively.