646
Anal. Chern. 1984, 56. 646-649
and the HFB group at C-15. The observation of the relatively large through-space anisotropic chemical shifts for H-5, H-7, H-1, H-2, and H-10 would indicate that in solution the conformation of the HFB group at (2-15 is freely rotating above the morphine system. The 'H NMR of 111' in Figure 7a showed the decided lack of high field multiple resonances of hydrogens at C-3 and C-4 which are prominent in I11 as illustrated in Figure 7b. This is readily justified by the introduction of the HFB group at C-4 and a double bond at C-3 to C-4. The isolated hydrogen at C-3 in 111' resonated at 7.276 ppm. Measured long range coupling of H-3 to H-1 (JS1= 1.0 Hz) established the validity of this chemical shift assignment. This also necessitated the HFB location at C-4. The substantial downfield shift of H-5 from 6.310 ppm in I11 to 7.859 ppm in 111' correlated well with the assigned C-4 location of the HFB group and the expected through-space anisotropic chemical shifts due to this group. Electron impact mass spectral analysis supported the structures assigned to I' and 111'. The structural characterization of 11' as well as the other HFB derivatives listed in Table I was confirmed by CINIMS.
481-81-2; HFBA, 336-59-4; heroin, 561-27-3.
LITERATURE CITED (1) Sobol, S. P.; Sperllng, A. R. ACS Symp. Ser. 1075, No. 73, 170. (2) Moore, J. M. I n "Instrumental Applicatlons in Forensic Drug Chemistry"; Klein, M., Kruegel, A. V., Sobol, S.P., Eds.; U.S. Government Printing Offlce, Washlngton, DC, 1978; pp 180-201. (3) Allen, A. C.; Moore, J. M.; Cooper, D. A. J . Org. Chem. 1083, 4 8 , 395 1. (4) Lurie, I.S.; Sottolano, S. M.; Blasof, S. J. J. Forenslc Scl. 1082, 27, 519. (5) Baker, P. B.; Gough, T. A. J. Chromatogr. Scl. 1081, 79, 483. (6) Neumann, H.; Gloger, M. Chromatographla 1082, 76,261. (7) Barron, R. P.; Kruegel, A. V.; Moore, J. M.; Kram, T. C. J. Assoc. Off. Anal. Chem. 1074, 57, 1147. (8) Stromberg, L. J. Chromatogr. 1075, 706,335. (9) Moore, J. M. J. Assoc. Off. Anal. Chem. 1073, 56,1199. (10) Drozd, J. J. Chromatogr. 1075, 773,303. (11) Ahuga, S. J . Pharm. Sci. 1078, 65,163. (12) Rice, K. C.; May, E. L. J . Heterocycl. Chem. 1077, 1 4 , 665. (13) Rice, K. C.; Jacobson, A. E. J . Med. Chem. 1075, 78, 1033. (14) Bentley, K. W. "The Chemistry of the Morphine Alkaloids", Oxford at the Clarendon Press: New York, 1954. (15) Craig, J. C.; Purushothaman, K. K. J. Org. Chem. 1070, 35, 1721. (16) Allen, A. C.; Moore, J. M.; Cooper, D. A., unpublished work, Drug Enforcement Agency, McLean, VA, 1983. (17) Hofmann, H.; Meyer, 8.; Hofmann, P. Angew. Chem., Int. Ed. Engl. 1072, 7 7 , 423. (18) Fraser, R. R.; Swlngle, R. B. Tetrahedron 1080, 25,3469.
Registry No. I, 86993-77-3;Ib, 86993-78-4; 11, 639-46-3; 111, 128-62-1;IV, 76-57-3; V, 57-27-2; VI, 2784-73-8; VII, 5140-28-3; VIII, 60223-55-4;IX, 7679-20-1;X, 58772-72-8;XI, 466-97-7;XII,
RECEIVED for review November 10, 1983.
Accepted January
9, 1984.
Determination of Platinum and Palladium in Geologic Samples by Ion Exchange Chromatography with Inductively Coupled Plasma Atomic Emission Spectrometric Detection R. J. Brown* and W. R. Biggs Chevron Research Company, Richmond, California 94802-0627
An alternative procedure to the classical fire assay method for determining Pt and Pd in sulfide ores, concentrates, and furnace mattes is presented. A suitable amount of sample is digested with aqua regia and filtered and any remaining gangue is digested with a mixture of HF and HCi04. The solution is flitered and the residue fused with sodium peroxide granules. The fused salts are dissolved in a dilute HCI acid soiutlon and ail three solutions combined. The resultant solution ls passed through a Bio-Rad AG 50W-X8 cation exchange resin in the H+ form. The chlorocompiex anions of Pt and Pd are not retalned by the catlon exchange resin whlle the base metal cations are efficiently removed from the eluent. Pt and Pd concentrations are subsequently determined with an inductively coupled plasma (ICP). Preliminary experiments showlng the method's potential expandabllity to Au are included.
Today's economic climate has stimulated a renewed interest in platinum group metals (PGM). While determining PGM by spectroscopic methods does provide a rapid and accurate means of analysis, base metals (large concentrations of nonplatinum group elements) present in the sample can create spectroscopic interference effeds. To eliminate this problem, 0003-2700/84/0356-0646$01.50/0
spectroscopic analyses incorporate either empirical interference corrections or a separation step to free the PGM from their base metal burden. Several separation-spectroscopic methods have been reported (1-10). The classical fire assay procedure using Pb (1, 4) or other metals (5-10) as collectors is perhaps the most frequently used procedure in the PGM refining industry. Despite the overwhelming contribution made by the fire assay procedure, achieving success with this sample preparation procedure hinges on the experience and knowledge of the assayer. To minimize the dependence on the assayer, other methods have been explored. The use of solvent extraction procedures ( 1 , I I ) have been widely reported in the analysis of PGM. This method, however, typically requires several time-consuming steps in the preparation procedure. Numerous chromatographic approaches (11-16) exist for separation. Specifically, separation of Pt and Pd from complex sample matrices can be carried out most directly by eluting the chlorocomplex anion of these metals through a cation exchange resin while retaining the base metal cations on the resin. This work compares the results obtained for the analysis of sulfide ore, concentrate, and furnace matte samples by both traditional fire assay procedures with various spectrometric detectors and ion-exchange chromatography with inductively 0 1984 American Chemical Society
ANALYTICAL CHEMISTRY, VOL. Table I. Instrument Specifications and Operating Conditions 1 m, Paschen-Runge mount direct spectrometer reader, vacuum, 1080 grooves/ mm grating, 50 pm exist slits Bausch and Lomb supplied, rf generator rated at 3 kW at 27.12 MHz forward incident power 1200 w reflected power
