Herbert V. Weiss

Cocrystallization of ultramicro quantities of elements with 2-mercaptobenzimidazole: Determination of gold in seawater

Abstract The cocrystallization of ultramicro quantities of 25 diverse elements with 2-mercaptobenzimidazole was investigated with the aid of radiotracers. Under optimum conditions Sn, Hg, Ag, Ta and Au were recovered in high yield. Distribution coefficients between mother liquor and solid phase were calculated for gold and were found to vary inversely with the degree of crystallization and the hydrogen ion concentration. The cocrystallization process was applied to the isolation and subsequent determination of the natural gold abundance in seawater. After radiometric correction for chemical yield, the concentration of gold was calculated to be 0.068 ± 0.003 μg 1 .

The co-crystallisation of ultramicro quantities of molybdenum with α-benzoinoxime determination of molybdenum in sea water

Abstract The co-crystallisation of ultrarnicro quantities of molybdenum with a-benzoinoxime was studied and conditions were established for the quantitative recovery of this element from very dilute solution. The information derived from these experiments was applied to the isolation and determination of molybdenum in sea water. After radiometric correction for its yield, the concentration of molybdenum in sea water was determined to be 12.2 ± 0.1 μg litre .

Iridium in sea-water.

Iridium in sea-water has been measured (after isolation from the saline matrix by reduction with magnesium) by neutron bombardment, radiochemical purification and high-resolution gamma-ray spectroscopy. The concentration obtained in a Pacific coastal water was 1.02 +/- 0.26 x 10(-14) g per g of sea-water. At such extremely low concentrations, seawater is an extremely unlikely source for anomalously high iridium concentrations measured in the Cretaceous-Tertiary boundary layer of deep-sea sediments.

Rapid isolation of radio-silver and certain other radio-elements from solution. Application to a search for 121Ag in 235U fission

Abstract : Rapid separation of Ag from Cd, In, and Sn was effected by filtration through a thin bed of Cu powder. This method was applied to a search for Ag121 in the thermal neutron fission of U235. None was detected and this result indicated that either the half-life of Ag121 is substantially shorter than the post-fission separation time of 3.5 sec or its yield is inordinately low. The study was extended to examine the behavior of an additional number of elements in the separation. Of the 28 elements studied, only Pd, Ag, Au and Hg were removed from solution to the extent of 70% or more. Se, Ru, Te and I were partly retained by the Cu to the extent of 5-33%. Of the remaining 20 metals, with the exception of Zr and As, appreciably less than 0.1% of the element adhered to the filter bed. This selectivity may alloy wider application of the method.