AC BRIEFS

Highlights of the scientificand technical articles in this issue. Quantitative Measurement of Hydrogen Types .... RICHARD B. KESLER, Engineering and T...
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AC BRIEFS Highlights of the scientific a n d technical articles in this issue

Quantitative Measurement of Hydrogen Types by Integrated Nuclear Magnetic Resonance Intensities Absorption bands for nonequivalent groups of protons in 26 selected pure compounds were integrated to determine percentages of total hydrogen content. T h e results were compared with theory. The effect of r.f. field strength on the integrals was studied. J. L. JUNGNICKEL and J . W . FORBES, Shell Development Co., Emeryville, Calif. Anal. Chem. 35, 938 (1963)

Detection and Identification of Mercaptans by Gas Liquid Chromatography The mercaptan sample is treated with disulfide; a second portion of the sample known mercaptan and this is converted disulfides. Trie technique provides nearly fication of the mercaptans.

iodine to form is spiked with a to a mixture of absolute identi-

K. F. SPOREK and M. D. DANYI, Owens-Illinois Technical Center, Toledo 7, Ohio Anal. Chem. 35, 956 (1963)

of

A High Sensitivity Scanning Coulometer with Automatic Background Correction and Proportional Scan Rate. Titration of Plutonium and Other Redox Species

The Beer-Lambert law is used as a model for a study of atomic absorption. It is shown that the sensitivity of measurement is a function of the lenglh of the absorbing flame path and of the reflectivity of the surrounding cell surfaces. T h e described absorption cell increases the sensitivity of detection of many elements.

Coulomb-potential curves of reversible processes under nearly equilibrium conditions are recorded with a scanning coulometer. T h e instrument is used for the direct determination of plutonium in irradiated nuclear fuel at the 2- to 5-/tg. level with a precision of 2 . 1 % .

The Physical Basis of Analytical Atomic Absorption Spectrometry. The Pertinence the Beer-Lambert Law

KEIICHIRO FUWA and BERT L. VALLEE, Biophysics Research Laboratory of the Division of Medical Biology, Department of Medicine, Harvard Medical School, and the Peter Bênt Brigham Hospital, Boston, Mass. Anal. Chem. 35, 942 (1963)

Application of Tiime of Flight Mass Spectrometry and Gas Chromatography to Reaction Studies

R. C. PROPST, Savannah River Laboratory, E. I. du Pont de Nemours & Co., Ailcen, S. C. Anal. Chem. 35, 958 (1963)

Electrolysis Cell for Continuous External Generation of Reagents in Reagent-Addition Analyzers

The described technique is applicable to any thermal, photochemical, or catalytic reaction carried out in a flow stream. Gas chromatographic peaks are identified with the mass spectrometer while quantitative analysis is determined by chromatographic peak areas.

The cell features single-piece, strong, compact construction; low generator-electrolyte consumption; and attainment of high current values for reagent generation at 100% current efficiency. It is capable of producing standard iodine solutions of about 0.08Λ7 concentration and bromine solutions of about 0.2.iV concentration.

E. J . LEVY, E. D. MILLER, and W . S. BEGGS, The Atlantic Refining Co., Philadelphia, P.a. Anal. Chem. 35, 946 (1963)

RICHARD B. KESLER, Engineering and Technology Section, The Institute of Paper Chemistry, Appleton, Wis. Anal. Chem. 35, 963 (1963)

Separation of Sonne Alkaloids, Steroids, and Synthetic Compounds by Thin-Layer Chromatography Preparative thin-layer chromatography is used to separate alkaloids, steroids, and synthetic compounds in amounts of 100 to 500 mg. A detailed account of the procedure, equipment, and examples of application is given. B. P. KORZUN, LOUIS DORFMAN, and S. M. BRODY, Research Department, CIBA Pharmaceutical Co., Division of CIBA Corp., Summit, N. J . Anal. Chem. 35, 950 (1963)

The Chromatographic Determination of Trace Amounts of Polynuclear Hydrocarbons in Petrolatum, Mineral Oil, and Coal Tar Analysis of petrolatums, mineral oils, and coal tar for polynuclear hydrocarbons by adsorption chromatography, solvent partition, and paper chromatography is discussed. Gas chromatography appears more sensitive than other analytical methods for polynuclear hydrocarbons. W I L L I A M LIJINSKY, IRVING DOMSKY, GLORIA MASON, HUSNI Y. R A M A H I , and TAHER SAFAVI, Division of Oncology, The Chicago Medical School, 2020 West Ogden Ave., Chicago 12, III. Anal. Chem. 35, 952 (1963)

Polarographic Analysis of a Series of Ion l-Hydroxypyridine-2-thione Systems

Metal

A polarographic study is reported on the copper-, zinc-, cadminum-, iron-, and nickel-l-hydroxypyridine-2thione systems. In the copper, zinc, and cadmium cases, the polarograms showed separate waves for the complexed and uncomplexcd organic moieties, and for the complexed and uncomplexcd metal ions. A L A N F. KRIVIS, EUGENE S. GAZDA, GEORGE R. SUPP, and MARTIN A . ROBINSON, Central Analytical Laboratories, Olin Mathieson Chemical Corp., New Haven, Conn. Anal. Chem. 35, 966 (1963)

The Dead-Stop Titration of Indium Indium is determined by dead-stop titration with hcxacyanoferrate(II). Mole ratios of five indium(III) to four hexacyanoferrate(II) were obtained, in agreement with previously reported ratios. L. S. MARTENS and HERSCHEL FRYE, Department of Chemistry, University of the Pacific, Stockton 4, Calif. Anal. Chem. 35, 969 (1963) VOL. 35, NO. 8, JULY 1963 · 9 A

BRIEFS Determination of Trinitrotoluene in W a r h e a d Exudates by Linear Sweep Polarography The method is based on the presence of only microgram amounts of T N T in. a 2 5 % acetone and 7 5 % O.lAf lithium chloride solution and depends on t h e measurement of the wave produced by the T N T at —0.66 volt vs. a Hg pool in this solution. T N T can be determined in a few min­ utes using an X-Y recorder with a linear sweep polarograph. G E R A L D C . W H I T N A C K , Chemistry Division, Research Depart­ ment, U . S. N a v a l O r d n a n c e Test Station, China Lake, C a l i f .

A Scheme for the Separation of Platinum, Palladium, Rhodium, and Iridium by Solvent Extraction The iodide complexes of platinum and palladium are ex­ tracted with tributyl phosphate, thereby separated from rhodium and iridium. Modifications of existing methods are used for the separation of palladium from platinum and for the separation of iridium from rhodium. G . H . FAYE and W . R. I N M A N , M i n e r a l Sciences Division, Mines Branch, Department of Mines and Technical Surveys, O t t a w a , Canada A n a l . C h e m . 35, 985 ( 1 9 6 3 )

A n a l . C h e m . 35, 9 7 0 ( 1 9 6 3 )

Behavior of Dialkyl Phosphorodithioic Acids in Liquid Extraction Systems

Potentiometric Titration of Acids in an Ν,Ν-Dimethyl FaWy Amide In the method a conventional glass indicating electrode is used with a saturated calomel reference electrode modi­ fied by replacing the saturated potassium chloride with a saturated aqueous solution of lithium chloride. T h e solvent is shown to be effective, especially for differen­ tiating titrations. C H A R L E S A . R E Y N O L D S , J A M E S LITTLE, and MERLE P A T T E N G I L L , D e p a r t m e n t of Chemistry, University of Kansas, Lawrence, Kan. A n a l . C h e m . 35, 973 ( 1 9 6 3 )

Determination of Hexafluorophosphate by Amperometric Titration with Tetraphenylarsonium Chloride The indicating ion is tetraphenylarsonium, and supporting polarographic data on the method is given. T h e results from the method are shown to agree well with those of the Nitron determination of this fluoride complex. H A R O L D E. A F F S P R U N G and V E R N O N S. A R C H E R , Depart­ ment of Chemistry, The University of Oklahoma, N o r m a n , O k l a .

The solubility and acidity of the diethyl, diisopropyl, din-butyl, and diisobutyl esters of phosphorodithioic acid in water and the distribution of each between CCL, methyl isobutyl ketone, or n-amyl acetate and HCl-NaCl solu­ tions was studied. Acid dissociation constants and parti­ tion coefficients were calculated. R A O U E L H . Z U C A L and Chemistry, University of T H O M A S H. HANDLEY, Ridge National Laboratory,

J O H N A . D E A N , Department of Tennessee, Knoxville, Tenn., and A n a l y t i c a l Chemistry Division, O a k O a k Ridge, Tenn. A n a l . C h e m . 35, 988 ( 1 9 6 3 )

Di-n-butyl Phosphorothioic Acid as an Extractant for Metal Ions Λ study was made of the extraction of metal ions from aqueous solutions of HC1 or H2SC>4 using di-n-butyl phos­ phorothioic acid. Of 32 metal ions studied, 18 extracted in significant amounts. T H O M A S H . H A N D L E Y , A n a l y t i c a l Chemistry Ridge N a t i o n a l Laboratory, O a k Ridge, Tenn.

Division,

Oak

A n a l . C h e m . 35, 991 ( 1 9 6 3 ) A n a l . C h e m . 35, 9 7 6 ( 1 9 6 3 )

Polarographic and Coulometric of Technetium

Determination

Technetium in any oxidation state can be readily con­ verted to T c ( V I I ) , so the determination of T c ( V I I ) will cover most situations in which technetium is to be deter­ mined. T h e polarographic determination of Tc, based on the measurement of wave I at p H 2, provides optimum selectivity and sensitivity. However, Tc can also be determined by measurement of wave I, I I , or I I I at p H 13. G . B. S. S A L A R I A , C H A R L E S L. RULFS, and P H I L I P J . E L V I N G , The University of M i c h i g a n , A n n A r b o r , M i c h .

Anion Exchange Studies in T a r t r a t e Medium. The Separation of M a n g a n e s e ( I I ) , C o b a l t ( l l ) , Z i n c ( l l ) , C o p p e r ( l l ) , and I r o n ( l l l ) Radioisotopes were used for batch equilibrium studies at various p H values and tartrate concentrations and also for following the column separations. M n ( I I ) , C o ( I I ) , Z n ( I I ) , C u ( I I ) , and F e ( I I I ) were successfully separated with Dowex 2-X8 resin in the tartrate form. G E R A L D F. PITSTICK, T H O M A S R. SWEET, and G E R A L D P. M O R I E , Department of Chemistry, The O h i o State University, Columbus 10, O h i o A n a l . C h e m . 35, 995 ( 1 9 6 3 )

A n a l . C h e m . 35, 9 7 9 ( 1 9 6 3 )

Liquid-Liquid Extraction of Pertechnetate with Methyltricaprylammonium Chloride

Ion

T h e formation of a, 1:1 pertechnetate-organic cation adduct seems to be necessary for the extraction at any p H . The competition of t h e chloride ion in the liquid-liquid anion exchange system described was studied. G . B. S. S A L A R I A , C H A R L E S L. RULFS, and P H I L I P J . E L V I N G , University of M i c h i g a n , A n n Arbor, M i c h . A n a l . C h e m . 3 5 , 983 ( 1 9 6 3 )

The Determination of Plutonium by dinitrilo) tetracetic Acid Titration

(Ethylene

In a direct procedure a solution containing 8 to 40 mg. of plutonium is buffered between p H 2.5 and 3.0, heated to boiling, and titrated with E D T A to a Cu—l-(2-pyridylazo)-2-naphthol end point. An indirect procedure is given which is a continuation of the direct procedure. Standard deviation data are given. W . B. B R O W N , D. R. R O G E R S , E. A . M E R S H A D , and W . R. A M O S , Monsanto Research C o r p . , M o u n d Laboratory, Miamisburg, O h i o A n a l . C h e m . 3 5 , 1000 ( 1 9 6 3 )

VOL. 35, NO. 8, JULY 1963 · 1 1

A

BRIEFS A Continuous Photometric Fluorine Analyzer Elemental fluorine in gas mixtures is measured by passing the sample stream through hot sodium chloride. T h e fluorine quantitatively liberates chlorine, which is meas­ ured at 360 m/i in a pressure-controlled flow colorimeter cell. T h e relative standard deviation of t h e analyzer is about ± 1 . 5 % above 0.8% fluorine. T h e standard de­ viation is about ±0.04 at lower levels. C . W . WEBER and O . H . H O W A R D , Technical Division, O a k Ridge Gaseous Diffusion Plant, Union C a r b i d e Nuclear C o . , O a k Ridge, Tenn. A n a l . C h e m . 35, 1002 ( 1 9 6 3 )

The Ultraviolet Spectrometric Determination of the Three Isomeric Toluenesulfonic Acids in Excess of Aqueous Sulfuric Acid T h e procedure involves the multicomponent spectrophotometric analysis of the sulfuric acid solution based on the ultraviolet absorption of the sulfonic acids. T h e absorbances of the unknown mixture and of its constitu­ ents, gathered at a large number of wavelengths, are sub­ jected to a least square treatment by an electronic com­ puter. H A N S C E R F O N T A I N , H E R M A N G . J . D U I N , and L E O V O L L BRACHT, Laboratory for O r g a n i c Chemistry, University of Amsterdam, The Netherlands

Comparison of Two Colorimetric Methods for Determination of Copper in Mineral Oils The carbamate method is compared with the neocuproine method for copper in the range of 2 to 200 μ%. of copper. The carbamate method is more sensitive but requires modification if iron is present. Precision and accuracy data are given. J . M . H O W A R D and H . O . S P A U S C H U S , M a j o r Laboratories, G e n e r a l Electric C o . , Louisville, Ky.

Appliances

A n a l . C h e m . 35, 1016 ( 1 9 6 3 )

Quantitative Radiochemical Procedure for the Analysis of Polonium-210 and Lead-212 in Minerals The procedure involves spontaneous electrodeposition on silver for the isolation of polonium-210 and controlledpotential electrogravimetric separation of lead-212 plus added lead carrier. Amounts of deposited nuclides are then determined by alpha counting. T h e method was applied to four zircon samples and one uranothorite sample. H . T. M I L L A R D , Jr., Division of G e o l o g i c a l Sciences, C a l i f o r n i a Institute of Technology, Pasadena, C a l i f . A n a l . C h e m . 35, 1017 ( 1 9 6 3 )

A n a l . C h e m . 35, 1005 ( 1 9 6 3 )

Spectrophotometiric Hydroperoxide Determination by the Use of Triphenylphosphine The decrease in absorbance at 260 ναμ when triphenyl­ phosphine is oxidized t o triphenylphosphine oxide by a hydroperoxide is a quantitative measurement of the hydroperoxide present. T h e procedure is compared with iodometric and ferric thiocyanate methods. ROBERT A . STEIN and V I D A S L A W S O N , Department of Biologi­ cal Chemistry, University of C a l i f o r n i a , Los Angeles 24, C a l i f . A n a l . C h e m . 35, 1008 ( 1 9 6 3 )

General Applicability of the Channels Ratio Method of Measuring Liquid Scintillation Counting Efficiencies The behavior of the curves of efficiency vs. channels ratio is examined as a function of small changes in photomultiplier and discriminator voltages, and the over-all accu­ racy of the method is assessed. Advantages of the chan­ nels ratio method over internal standardization or dilu­ tion techniques for determining efficiency are discussed. E L I Z A B E T H T. B U S H , N u c l e a r - C h i c a g o C o r p . , 333 East H o w a r d Ave., Des Plaines, I I I . A n a l . C h e m . 35, 1024 ( 1 9 6 3 )

Spectrophotometiric Titration of Some Divalent Metals in Chloroform—Isopropyl Alcohol Solvent Mixture

Neutron Activation and Radiochemical Determination of the Molybdenum, Chromium, and Iron Content of Individual Stainless Steel Microspheres

Dimethylglyoxime was used as a titrant. Spectrophoto­ m e t r y titrations of 0.4 to 4 /imoles of N i ( I I ) in 40 ml. of 1:1 chloroform—isopropyl alcohol solvent gave an over­ all precision of 3 parts per thousand. Co(II) in amounts of 1 to 4.5 /iinoles was titrated with a precision of 2.5 parts per thousand. T h e influence of other metal ions was studied.

Diameters of stainless steel microspheres, weighing be­ tween 4.7 χ 10~9 and 3.9 χ 10"8 gram, are measured by optical microscopy. After encapsulation in lead foil and irradiation with an intense flux of neutrons, radiochemical procedures are used to isolate Mo™, Ci*1, Fe 55 · 59 , and Np 238 . T h e sources of errors in the method are reported.

of Chemistry,

P H I L I P A . B E N S O N and CHESTER E. G L E I T , Tracerlab, Divison of Laboratory for Electronics, Richmond, C a l i f .

A n a l . C h e m . 3 5 , 1010 ( 1 9 6 3 )

A n a l . C h e m . 35, 1029 ( 1 9 6 3 )

R. K. B E H M and R. J R O B I N S O N , Department University of W a s h i n g t o n , Seattle 5, W a s h .

Spectrophotometiric Determination of Aldrin Aldrin is converted to dihydroaldrin nitrosochloride. This compound forms dihydrochlorketoaldrin, which in turn, reacts with TO-dinitrobenzene and potassium hydrox­ ide to give a violet-red chloroform-extractable derivative. The resulting solution obeys Beer's law over the range 0 to 100 iug. H A K O N O . FRIESTAD, D e p a r t m e n t of Pharmacology and Toxi­ cology, The Veterinary C o l l e g e of Norway, Oslo, N o r w a y A n a l . C h e m . 3 5 , 1012 ( 1 9 6 3 )

Novel Radiotracer Method for Fluoride Determination Using selective conditions, tantalum-182 is extracted from 6.5AÎ sulfuric acid solution as a fluoride complex into diisobutylketone. T h e radioactivity of the extractant is proportional to the fluoride ion concentration. Applications of the method are discussed. F L E T C H E R L. M O O R E , A n a l y t i c a l Chemistry Ridge N a t i o n a l Laboratory, O a k Ridge, Tenn.

Division,

Oak

A n a l . C h e m . 3 5 , 1032 ( 1 9 6 3 )

VOL. 35, NO. 8, JULY 1963 · 1 3

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BRIEFS Fluorescence Techniques in the Microdeterminaticn of Metals in Biological Materials. Utility of 2.4-Bis-[N,N-di-tcarboxymethyDaminomethyl] fluorescein in the Fluorometric Estimation of A I + 3 , Alkaline Earths. C o + 2 . Cu+ 2 . N i + 2 , and Zn+ 2 in Micromolar Concentrations

Semimicro Determination of Molecular Weight with a Dew-Point System

Spectral and fluorescent changes accompanying the reac­ tion of aluminum, the alkaline earth metals, cobalt, cop­ per, nickel, and zinc with 2,4-bis-[iV,./V'-di-(carboxymethyl) aminomethy] ] fluorescein have been studied as a function of p H and of concentration of the reactants.

ANGELO DE ROS, OLIVIERO FAGIOLI, and PIERO SENSI, Research Laboratories, Lepetit S.p.A., Milan, Italy

The method described, based on the vapor pressure lowering of a solution, is easy to perform and is shown t o provide good precision and accuracy. Molecular weight determinations below 500 have been made. Solvents having boiling points between 40° and 120° C. can be used.

Anal. Chem. 35, 1054 (1963)

DONALD F. HOELZL W A L L A C H and THEODORE L. STECK, Harvard University Medical School, Boston 15, Mass. Anal. Chem. 35, 1035 (1963)

The Separation and Fluorescent X-Ray Spectrometric Determination of Zirconium, Molybdenum, Ruthenium, Rhodium, and Palladium in Solution in Uranium-Base Fissium Alloys Palladium is precipitated with dimethylglyoxime, the precipitate is extracted with chloroform. T h e aqueous portion, made 6M in HC1, is passed through a Dowex 1-X8 anion exchange resin. Zirconium and rhodium do not adsorb, uranium is eluted with 0.03M HC1, ruthenium and molybdenum with 8M H N 0 3 . T h e elements are then determined by x-ray fluorescence. J . O. KARTTUNEN, Argonne National Laboratory, Argonne, III. Anal. Chem. 35, 1044 (1963)

The Use of Perchloric Acid in Propellants Analysis After oxidation of propellants in h o t perchloric acid, lead, aluminum, copper, and potassium can be determined easily and precisely. T h e sulfate content can be esti­ mated by precipitation as barium sulfate from the per­ chloric acid solution. T h e described procedure has proved to be safe. J. B. MACORKINDALE and J . J . LAMOND, Chemical Inspec­ torate, Royal Arsenal, Woolwich, London, S.E. 18, England Anal. Chem. 35, 1058 (1963)

Rapid Titrimetric Determination of Orthophosphate with Cerous Ion. Applications to Technical Grade Inorganic Phosphates Orthophosphate is titrated with cerous ion in a buffered medium at p H 7.0 t o 9.5 using Eriochrome Black Τ indi­ cator. Accuracy and precision data on the method are given, and the interfering ions are considered. T. A . TAULLI and R. R. IRANI, Research Department, Inorganic Chemicals Division, Monsanto Chemical Co., St. Louis, Mo.

X-Ray Emission Analysis of Plutonium and Uranium Compound Mixtures Refractory oxide mixtures or alloys are fused in a flux of potassium pyrosulfa~e. T h e flux mixture is cast in such a way as to provide slow cooling. La lines of uranium and plutonium produced by x-ray emission are measured. Thorium is used as an internal standard. OSCAR MENIS, E. K. HALTEMAN, and Ε. Ε. GARCIA, A d ­ vanced Materials Center, Nuclear Materials and Equipment Corp., Apollo, Pa.

Anal. Chem. 35, 1060 (1963)

Assay of Aziridinyl Compounds Methanol-soluble aziridinyl compounds are assayed by reacting them with excess thiocyanic acid, generated in situ from potassium thiocyanate and p-toluene sulfonic acid, and back-titrating with methanolic potassium hy­ droxide.

Anal. Chem. 35, 1049 (1963) R. C. SCHLITT, Methods Development Section, Chemical and Materials Laboratory, Aerojet-General Corp., Sacramento, Calif. Anal. Chem. 35, 1063 (1963)

Inert Gas Fusion Determination of Oxygen in Vanadium, Niobium, and Tantalum Oxygen in vanadium is determined by a platinum flux technique, while oxygen in niobium and tantalum is de­ termined with a mixed nickel-platinum bath with a platinum flux technique. T h e method permits determina­ tion of oxygen consents from 100 to 1000 p.p.m. with a relative standard deviation of 3 % for vanadium and 5% for niobium and tantalum. GEORGE J . K A M I N , JEROME W . O'LAUGHLIN, and CHARLES V. BANKS, Institute for Atomic Research and Department of Chemistry, Iowa State University, Ames, Iowa Anal. Chem. 35, 1053 (1963)

Elimination of Chloride Interference in the Chemical Oxygen Demand Test The procedure requires the addition of mercuric sulfate to the sample forming a soluble mercuric chloride com­ plex that resists oxidation under conditions of the chemi­ cal oxygen demand test. Results are presented on pure organic solutions and various sewage effluents containing known amounts of chloride. RICHARD A . DOBBS and ROBERT T. WILLIAMS, Robert A. Taft Sanitary Engineering Center, 4676 Columbia Parkway, Cin­ cinnati 26, Ohio Anal. Chem. 35, 1064 (1963) VOL. 35, NO. 8, JULY 1963 · 1 5 A

BRIEFS Determination of Surface Areas of Phosphates from Adsorption Measurements in Nonaqueous Media

The Heart of the Norelco Electromagnetic Optical System

The method is based on the Langmuir equation for ad­ sorption and it utilizes common laboratory reagents and equipment. Phosphates with surface areas between 1.3 and 71 sq. meters pel' gram arc determined in acetic acid— toluene solutions. R. E. MESMER and R. R. IRANI, Research Department, Inorganic Chemicals Division, Monsanto Chemical Co., St. Louis, Mo. Anal. Chem. 35, 1067 (1963)

Spectropolarimetiry. Acid-Base Titrimetry with Asymmetric Indicators and Determination of Metal Ions and Asymmetric Substances A high-precision photoelectric spectropolarimeter is used to determine optical rotation at many different wave­ lengths. T h e instrument is applied t o the titration of acids or bases using optically active substances as indi­ cators. Metal ions, asymmetric coordinating agents, and ligand-metal ion ratios in coordination compounds can be determined. STANLEY KIRSCHNER and DINESH C. BHATNAGAR, Wayne State University, Detroit, Mich. Anal. Chem. 35, 1069 (1963)

®

Norelco

Radioactivation Analysis of Sodium by Counting Photoneutrons Na=* is assayed by counting photoneutrons emitted from deuterium by t h e 275-m.e.v gamma ray, in an assembly consisting of D 2 0 and neutron detectors. Microgram quantities of sodium were analyzed with a precision of 2 % . Sensitivities better than 0.1 ,ug. are indicated. SAADIA AMIEL and M A X PEISACH, Israel Atomic Energy Commission, Soreq Research Establishment, P. O. B. 527, Rehovoth, Israel

EXCUUSIVE "IMMERSION" OBJECTIVE LENS

Anal. Chem. 35, 1072 (1963)

Diffuse Reflectance Spectra of Potassium lodate and Some Mercuric Iodide Complexes Diffuse reflectance spectroscopy in t h e U V was studied using KlOa variously diluted with an inactive diluant, LiF. Results of a semiquantitative nature at wavelengths down to 220 χημ were obtained by using some precautions. T. R. GRIFFITHS, North East Essex Technical College, Colchester, England Anal. Chem. 35, 1077 (1963)

Anion Exchange Separation of Magnesium and Calcium with Alcohol-Nitric Acid A "column separation factor" is proposed and used in selecting the best eluting medium for the anion exchange separation of magnesium and calcium. A solution of 0.5M nitric acid in 90% isopropyl alcohol is t h e eluent, and Amberlyst XN-1002 is used as the anion exchange resin. JAMES S. FRITZ and HIROHIKO W A K I , Institute for Atomic Research and Department of Chemistry, Iowa State University, Ames, Iowa Anal. Chem. 35, 1079 (1963)

with rod-type holder a Hows specimen—to be "immersed"directly into the heart of objec­ tive lens»to be easily manip­ ulated for stero orientation \ studies, high/low temperature v studies, and tensile studies · to be dry-box loaded and transferred to micro­ scope without atmospheric contact · to be simultaneously compared with another specimen.

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VOL. 35, NO. 8, JULY 1963 · 1 7 A