NEWS
TRANSIST0RI7M
achieves selectivity in anion exchange separations by nse of variable concentrations of HC1 or HCl-HF solutions. Coordination Kinetics in Separations. Differences in rates of reaction of complex ions rather than equilibrium properties can be applied to the separation of metal ions, said D. W. Margerum, Purdue University. The actual physical separation of different complex ions first must be compared to the coordination rate. Ion exchange resins arc useful for separations of this type. To achieve reactions which arc sufficiently slow with common metal ions, it is necessary to use strong complexing ligands. Polarography of Metal Complexes. Complex ions are used in polarographic RCLiac 1 2 8 C h a n n e l S e a l e r - A n a l y z e r peranalytical methods to shift half-wave potentials of metals, thus separating forms every operation from gross counting through interfering waves, R. L. Pecsok, Uniscintillation spectroscopy with the finest precision versity of California, stated. Comand reliability. The rugged instrument may be plexes are also used to "mask" interused either as a 1 25-channel scaler or a 1 28- fering ions, to improve the shape of poorly defined irreversible waves, and channel analyzer. For complete information on to prevent precipitation of certain both transistorized and vacuum tube multi-channel metal ions at high pH. Polarographic data are also used to analyzers, write: Dept. 2 8 9 Much the nature of complex ions, their properties, stabilities, and reactions. Multidentate Ligands. The reac5121 W. Grove, Skokie, III., U.S.A. ORchard 3-8700 tions and potentiometric titrations of highly charged metal ions with multiCircle No. 133 on Readers' Service Card dentate ligands were described by A. E. Martell, Clark University. New P r e c i s i o n ! N e w C o n v e n i e n c e ! New V e r s a t i l i t y ! Multidentate chelating agents, such as EDTA, which give simple titration curves with divalent metals, interact with metal ions of higher charge to give relatively complex titration curves. He illustrated this point with results obtained with iron (III), zirconium (IV), features: and thorium (IV). EXTRA-FINE, HIGH INTENSITY FOCAL SPOT EDTA in the Paint Industry. . . . best for all diffraction studies Many important materials used in the . . . ideal for large lattice structures paint industry contain only one determinable element, said C. A. Lucchesi, Sherwin-Williams Co. For this reason, Brilliant point source offers unEDTA is used as a universal titrant for matched performance in diffraction quality control testing of driers and analyses of natural and synthetic pigments. To determine a number of fibers, plastics, waxes, grease, elements, as in mixed pigment systems, steroids, proteins, pharmaceuticals; masking agents and pH adjustment are in metals research. Extra-fine, high used. Titrations in alcohol-benzene intensity microsource assures fastONLY MICRO-FOCUS OFFERS: solutions have simplified the producest exposure on large lattice ma• Greater x-ray flux tion control testing of driers, which are terials or microsamples. No need • Less scattered radiation metallic salts of carboxylic acids. for large, hard-to-grow crystals. • Superior resolution Optical Rotation. The use of optiWrite for new catalog today. • Shortest exposure cal rotation measurements to determine the structure and stability of V£ir *.·•*• metal complexes was outlined by R. S. EXCELLENT FOR X-RAY MICRORADIOGRAPHY: Hilger Micro-Focus lends itself t o Juvet, Jr., University of Illinois.
RCLiac 128
Compact
Lightweight
Reliable
RADIATION COUNTER LABORATORIES, Inc.
Hilper
MICRO-FOCUS X-RAY UNIT
many applications in studies o f b i o l o g i c a l microstructures: microporosity and inclusions in metals; microparticle analyses in criminology, etc. Interchangeable 4 0 a n d 1 0 0 micron f o c a l spots sharpen details in l a r g e r a d i o g r a m s
JAco
Jarrell-Ash Company 32 Farwell street, Newtonville 60, Massachusetts Circle No. 120 on Readers' Service Card
44 A
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ANALYTICAL CHEMISTRY
' £L·. _U
Spectroscopy Session at ASTM Meeting The Third Pacific Area National Meeting of the American Society for Testing Materials will include a svm-
