Determination of zinc in iron meteorites by neutron activation analysis

The determination of a trace amount of zinc in some iron meteorites was done by a neutron activation analysis using short-lived 52 minute 69Zn. Samples and a standard were irradiated simultaneously for 20 minutes in the JRR-1 reactor at the neutron flux of 3 × 1011 n/cm2/sec. After the irradiation the sample was dissolved in HNO3-HCl-H2SO4 mixture in the presence of zinc carrier. The induced activity derived from zinc was separated and purified from the matrix by acetylacetone-chloroform and isopropylether extractions, followed by an anion-exchange procedure. Finally zinc was precipitated as zinc mercury thiocyanate, and the β-activity of the purified isotope 69Zn was counted. The concentration of zinc in the sample was calculated by comparing the activity of radiochemically pure 69Zn isolated from the sample with that from the standard. The total time required for the completion of the whole procedure was three hours and a half, and the average chemical yield was 70%. The following results were obtained (in ppm). Canyon Diablo 34, 33, 35 Henbury 17, 70, 5.8, 9.4, 10, 16, 15, 12 Admire (metal phase) 2.8, 3.0