1.1 CHEMICALS
| Pt-ribbon (two vendors): |
High purity platinum (99.999%), thickness = 0.001", width = 0.02"
(H.Cross Company, 363 Park Ave. Weehawken, New Jersey 07087, USA) (high Os blank)
5N (99.999%) purity 1PC platinum (KNC 5693), thickness = 0.001"
|
|---|---|
| Cr (VI): |
Cr (VI) oxide, special products (Johnson Matthey). Dissolve 0.2 g
CrO3 per ml 4N H2SO4, intensely boiled to vaporize and remove Os. |
|
|
Fused - ground (Fisher Scientific 5252-10) |
| Na2CO3: | 2.5 kg, AR (high Os blank) (Mallinckrodt 7521) |
| Ni: | Ni-powder 100 mesh, 99.99%, 500 g (Aldrich 20,390-4) |
| S: | Sublimed S-powder, 500 g (J.T. Baker 4088-01) |
| H2SO4: | Ultrapure (Seastar) |
| HNO3: | Reagent grade (used only for cleaning) |
| HCI: | Ultrapure (quartz distilled or two-bottle distilled) |
| HBr: | Ultrapure (Seastar or two-bottle distilled) |
| HF: | Ultrapure (Seastar or two-bottle distilled) |
| Acetic acid: | Ultrapure (Seastar, concentrated solution) |
| H2O: | Milli-Q-UV (Millipore) |
| H2O2: | Analytical grade (J.T. Baker or Fisher) |
| Ba(NO3)2: | Prepared from analytical grade BaCO3. BaCO3 was dissolved in dilute HNO3 and repeatedly precipitated and redissolved in conc. HNO3. This converts all Ba to Ba-nitrate and oxidizes organics. Saturated solution in Milli-Q-UV H2O. |
| O2-gas: | Partial pressure of O2 in the mass spectrometer of ~0.6 x 10-6 mbar. Oxygen enhances the oxide speciation of Re and Os to ReO4- and by reducing the level of the subordinate oxides to background levels. It also improves the overall ionization efficiency for both species. |
1.2 RESIN
Os:
The resin has to be cleaned carefully using ultaclean reagents in a multi-step cleaning procedure as follows (Eric Hauri, pers. communication, 1993):
- - - - - OR, ACCORDING TO FALKNER (1992): - - - - -
The clean-up procedure takes advantage of the anion exchange properties of Chelex-20 at low pH (< 2)
conditions, under which protonation of OH- groups facilitates their exchangeability. This relatively weak anion-exchange resin is used over more basic forms because Os complexes show such high affinities (Kd's > 1013) for these resins that it becomes difficult to recuperate Os after absorption (Falkner, 1992).
Re:
Chelex 20 anion chelating resin (Na+-Form), 20 - 50 mesh, technical grade (Biorad 745-7000; or order 500 g jars, 200 - 800 µm, by telephone from Biorad). This is a styrene divinylbenzene copolymer containing paired iminodiacetat ions which act as chelating groups in binding metal ions for pH < 4.
(to put in OH--form, this step can probably be eliminated, because the NaOH contributes significantly to the blank and the resin is used at low pH, see Falkner, 1992)
AG1-X8 anion exchange resin, 200 - 400 mesh. Washed in Milli-Q H2O prior to use. Tiny particles floating on the surface should be thrown away together with dark particles at the bottom of the glass beaker (dirty beads, dirt ?).
1.3 SPIKES
Mixed PGE spikes: 99Ru, 105Pd, 190Os, 191Ir, 198Pt in various concentrations and ratios.
The spikes are obtainable from U.S. Department of Energy, c/o Martin Marietta Energy Systems, Inc., Oak Ridge National Laboratory, P.O. Box 2009, Oak Ridge, Tennessee 37831-8044, USA.
1.4 LABWARE
