A neutron activation method is proposed for the determination of trace quantity of copper, down to submicrogram level, in fats.
The sample and standard are irradiated for 5 hr at a neutron flux of 1.7×1O12N·cm-2·sec-1. The radiochemical separation consists of extraction of induced activity of 64Cu in hydrochloric acid from toluene solution of the irradiated fat, followed by the anion exchange in hydrochloric acid media. The activity is finally mounted as copper (II) sulfide. The activity measurement is taken on a NaI (Tl) crystal coupled with a 256 channel pulse height analyzer.
Radiochemical purity is satisfactory. The chemical yield averages 70.6%, and there is a considerable saving of time in the radiochemical work. The agreement is good for determinations of trace copper, by a colorimetric method preceded by dry ashing along with magnesium nitrate as an ashing aid, and by the neutron activation method. This method is therefore believed as giving a sound basis to the routine analytical work.
