A C BRIEFS Highlights of Articles in This issue
High Performance Liquid Chromatography on Small Particle Silica Gel
Support-Bonded Polyaromatic Copolymer Stationary Phases for Use in Gas Chromatography
Columns of 5-10 μπι silica gel have been packed by a high pressure slurry technique. H E T P values of less than 0.1 mm were obtained at practical flow velocities and 15 effec tive plates/sec were generated.
The preparation and use of porous polyaromatic copolymer stationary phases formed directly on a support surface are described. Dilution and cross-linking effects on copolymer properties are also discussed.
RONALD E. MAJORS, Varian Aerograph, 2700 Mitchell Drive, Walnut Creek, Calif. 94598 Anal. Chem., 44, 1722 (1972)
EDWARD N. FULLER, Applied Automation, Inc.—Systems Research Department, Bartlesville, Okla. 74004
Influence of Column Configuration on Performance in High Efficiency Liquid Chromatography Coiling packed columns in high performance liquid chro matography is shown to result in efficiency losses. Figure " 8 " geometries, however, are found to give no efficiency loss compared to straight columns. HOWARD BARTH, ERWIN DALLMEIER, and BARRY L. KARGER, Department of Chemistry, Northeastern Uni versity, Boston, Mass. 02115 Anal. Chem., 44, 1726(1972)
Anal. Chem., 44, 1747(1972) Electrochemical Cell as a Gas Chromatograph-Mass Spectrometer Interface Construction details and operating conditions for a palladium alloy, electrochemical, gas chromatograph-mass spectrometer interface are described. The cell removes more t h a n 99.9996% of the hydrogen carrier gas. W. D. DENCKER and D. R. RUSHNECK, Northgate Labora tories, Hamden, Conn. 06514, and G. R. SHOEMAKE, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, Calif. 91103 Anal. Chem., 44, 1753 (1972)
Characterization of Exponentially Modified Gaussian Peaks in Chromatography The use of slope and moment analysis in examining single and double exponentially modified Gaussian peaks is de scribed. These methods of analysis can be useful in detect ing and characterizing double peaks. ELI GRUSHKA, Department of Chemistry, State University of New York at Buffalo, Buffalo, N.Y. 14214 Anal. Chem., 44, 1733 (1972) Separation and Quantitative Determination of the Yttrium Group Lanthanides by Gas-Liquid Chromatography A rapid method combining synergistic extraction and g a s liquid chromatography has been developed for the separation of the yttrium group lanthanides. Percentage recovery of 97.1 with a relative mean deviation of ± 2 . 3 pph and a rela tive standard deviation of ± 3 . 1 pph is possible using linear analytical curves. CHARLES A. BURGETT and JAMES S. FRITZ, Institute for Atomic Research and Department of Chemistry, Iowa State University, Ames, Iowa 50010 Anal. Chem., 44, 1738 (1972)
Plasma Chromatography of the Mono-Halogenated Benzenes Both positive and negative plasmagrams have been obtained for monohalogenated benzenes. Characteristic patterns for each compound and evidence of dissociative electron capture by thermal electrons are shown. FRANCIS W. KARASEK and OSWALD S. TATONE, Depart ment of Chemistry, University of Waterloo, Waterloo, Ontario Anal. Chem., 44, 1758 (1972) Piezoelectric Detectors for Organophosphorus Compounds and Pesticides Quartz piezoelectric crystals coated with selective substrates have been used for the detection of organophosphorus com pounds and pesticides in the ppm range. EUGENE P. SCHEIDE and GEORGE G. GUILBAULT, Depart ment of Chemistry, Louisiana State University in New Or leans, Lakefront Campus, New Orleans, La. 70122 Anal. Chem., 44, 1764(1972)
Exact Treatment of Diffusion in Gas Chromatography
Apparatus for Automated Gel Permeation Cleanup for Pesticide Residue Analysis. Applications to Fish Lipids
A more precise theory for determining the contribution of diffusion to band spreading in GC has been devised. Ex periments yielded values of 0.62 for the interdiffusion coef ficient on nitrogen in helium and unity for the obstructive coefficient of Chromosorb P.
A system which allows unattended operation of a gel permea tion cleanup procedure for pesticide-containing fish lipid extracts is described. Automation results in significant savings in cost and time in pesticide residue analysis.
H. A. HARTUNG and R. W. DWYER, Philip Morris, U.S.A., Richmond, Va.
ROGER C. TINDLE and DAVID L. STALLING, Fish-Pesticide Research Laboratory, Columbia, Mo.
Anal. Chem., 44, 1743 (1972)
Anal. Chem., 44, 1768 (1972)
ANALYTICAL CHEMISTRY, VOL. 44, NO. 11, SEPTEMBER 1972
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13 A
AC BRIEFS Response of a Calcium-Selective Electrode in Acid Solutions
Rapid, Phase-Sensitive, Three-Electrode Alternating Current Polarography
An anomalous negative change in potential has been ob served in C a 2 + salt solution? at pH 3.0-5.0. This change is associated with the entry of water and calcium salts into t h e membrane and t h e formation of a barrier layer.
The application of phase-sensitive detection to short con trolled drop time ac polarography has allowed the develop ment of a rapid, accurate, and sensitive polarographic tech nique.
JOHN BAGG and ROBERT VINEN, Department of Industrial Science, University of Melbourne, 35 Royal Parada, Victoria 3052, Australia
A. M. BOND, Department of Inorganic Chemistry, University of Melbourne, Parkville, 3052, Victoria, Australia, and D. R. CANTERFORD, Department of Physical Chemistry, Uni versity of Melbourne, Parkville, 3052, Victoria, Australia Anal. Chem., 44, 1803 (1972)
Anal. Chem., 44, 1773 (1972)
Determination of Chromium in Biological Materials by Atomic Absorption Spectrometry Using a Graphite Furnace Atomizer
Successive Photometric Titration of Calcium and Magnesium A new, simple method for t h e determination of Ca and M g is presented. They are titrated successively with E G T A and D C T A at p H 11 using Phthalein Complexon as an indicator. HISAKUNI SATO and KOZO MOMOKI, Laboratory for In dustrial Analytical Chemistry, Faculty of Engineering, Yoko hama National University, Ooka 2-31-1, Minami-ku, Yokohama-shi, Japan Anal. Chem., 44, 1778 (1972)
A method which is simpler and more rapid than existing methods is presented for the determination of chromium in small samples (50-200 μΐ) of plasma or urine. T h e precision is about ± 5 % . I. W. F. DAVIDSON and W. L. SECREST, Department of Phar macology, Bowman Gray School of Medicine of Wake Forest University, Winston-Salem, N.C. 27103 Anal. Chem., 44, 1808 (1972) Ultrasonic Nebulization in a Low-Emission Flame for Atomic Fluorescence Spectrometry
Sam pied-Data Approach to the Reduction of Uncompensated Resistance Effects in Potentiostatic Experiments An iR compensator, based on t h e current-interrupt method of determining ohmic potential drop, is described. RICHARD BEZMAN, Department of Chemistry, Harvard University, 12 Oxford Street, Cambridge, Mass. 02138 Anal. Chem., 44, 1781 (1972)
Ultrasonic nebulization into a low-temperature flame has been investigated. Greater atomization efficiency, reduced light scattering, and lower flame emission contribute to the observed improved performance. Mi B. DENTON and H. V. MALMSTADT, Department of Chemistry, School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, III. 61801 Anal. Chem., 44, 1813(1972) Atomic Absorption Determination of Cadmium and Lead in Whole Blood by a Reagent-Free Method
Experimental Evaluation of Cyclic Voltammetry Theory for Disproportionation Reactions Reduction of sulfonephthalein acid-base indicators is used to evaluate the theory of cyclic voltammetry for disproportion ation reactions initiated electrolytically. P. J. KUDIRKA and RICHARD S. NICHOLSON, Michigan State University, East Lansing, Mich. 48823 Anal. Chem., 44, 1786(1972)
A simple method with reagent-free sample preparation is described for the analysis of cadmium and lead in whole blood. The relative detection limits are 0.2 ng/ml for cad mium and 2 ng/ml for lead. THOMAS R. HAUSER, THOMAS, A. HINNERS, and JANE L. KENT, Environmental Protection Agency, National Environ mental Research Center, Division of Health Effects Re search, Bio-Environmental Laboratory Branch, Research Triangle Park, N.C. 27711 Anal. Chem., 44, 1819 (1972)
Structural Determination of Monosubstituted Alkylbenzenes by Proton Magnetic Resonance
Colorimetric Determination of Calcium Using Reagents of the Glyoxal Bis(2-Hydroxyanil) Class
P M R parameters of 66 monosubstituted alkylbenzenes were determined by the complete analysis of the-spectra. A simple method is proposed for the structural determination of such compounds by P M R patterns.
The determination of calcium in solution (0.1—15 Mg/ml) is easy, accurate, and reproducible with reagents of the glyoxal bis(2-hydroxyanil) class. The sequence of adding the re agents is critical and chelates form at a high p H thereby limit ing interferences.
OSAMU YAMAMOTO, KIKUKO HAYAMIZU, KIYOHARU SEKINE, and SHUJI FUNAHIRA, Government Chemical Research Institute, Shibuya-ku, Tokyo, Japan Anal. Chem., 44, 1794 (1972)
CARL W. MILLIGAN and FREDERICK LINDSTROM, Depart ment of Chemistry and Geology, Clemson University, Clemson, S.C. 29631 Anal. Chem., 44, 1822(1972)
ANALYTICAL CHEMISTRY, VOL. 44, NO. 1 1 , SEPTEMBER 1972 ·
15 A
AC BRIEFS Quantitative Sampling from a Vertical Tube Reactor Preignition events in the vertical tube reactor have been sampled through quartz microprobes using critical orifice sampling. T h e point source samples are adiabatically quenched and representative of the components of the precombustion reactions. F. W . W I L L I A M S a n d W. L. S T U M P F , Jr., C h e m i c a l D y n a m i c s B r a n c h , C h e m i s t r y Division, Naval Research Laboratory, W a s h i n g t o n , D.C. 20390 A n a l . C h e m . , 44, 1829 (1972)
Critical Evaluation of the Karl Fischer Water Method, End-Point Detection System, and Standardization The parameters for end-point detection were evaluated re sulting in the design of a simple automatic titrator. Sodium tartrate contained occluded water, rendering it an unsatis factory fundamental water standard. T H O M A S H. BEASLEY, Sr., HOWARD W. ZIEGLER, RICHARD L. CHARLES, a n d PERRY K I N G , M a l l i n c k r o d t C h e m i c a l W o r k s , Post Office Box 5439, St. Louis, Mo. 63160 A n a l . C h e m . , 44, 1833 (1972)
Notes Chelation of Boric Acid with Nitropyrocatechols and the Photometric Determination of Boric Acid The first and second acidity constants of 3- and 4-nitro- and 3,5-dinitropyrocatechols and the stability constants of their boric acid chelates are reported. T h e sensitivity of photo metric determination of boron with 4-nitropyrocatechol is 0.015 mg/ml per unit absorbance. ERKKI J . HAKOILA, J O U K O J . K A N K A R E , A N D TAISTO S K A R P , D e p a r t m e n t of C h e m i s t r y , University of T u r k u , T u r k u 50, Finland A n a l . C h e m . , 44, 1857 (1972)
Precision and Detection Limits of Cadmium, Manganese, Cobalt, and Nickel in Sulfides by Electron Microprobe Analysis Minimum detectability limits for Cd and Mti in zinc sulfide and Ni and Co in iron sulfide were found to vary from 1380 ppm for Cd at 15 kV to 200 ppm for M a at. 20 kV excitation voltage. ROBERT H. HEIDEL, U.S. Geological Survey, Denver, Colo. 80225 A n a l . C h e m . , 44, 1860 (1972)
Kinetic Study of the Initial Cyclization of Methyl-bis(/3-chloroethyl)amine Hydrochloride Using Chloride Ion-Selective Electrodes
Isothermal Decomposition of Isothiocyanatopentammine Cobalt(lll) Perchlorate—Particle Size Effect The effect of particle size on t h e decomposition rate is ex plained on the basis of thermogravimetric analysis, infrared spectroscopy, and optical microscopic results. The complex dependence is interpreted primarily on t h e role of the initial product gas, ammonia, on further decomposition. CHIEH J U CHOU a n d FERRON A. OLSON, D e p a r t m e n t of M i n i n g , Metallurgical a n d Fuels Engineering, University of U t a h , Salt Lake City, U t a h 84112 A n a l . C h e m . , 44, 1841 (1972)
Determination of Nanogram Quantities of Simple and Complex Cyanides in Water Two methods are described. The first, a modification of the manual distillation process, has a detection limit of 5 μg/l CN. The second, an automated colorimetric method, lias a detection limit of 1 ,ug/l CN. PETER D. G O U L D E N , BADAR K. A F G H A N , a n d PETER B R O O K S B A N K , Water Quality Division, Inland Waters B r a n c h , E n v i r o n m e n t C a n a d a , 45 Spencer Street, O t t a w a , K1Y 1P5, Canada A n a l . C h e m . , 44, 1845 (1972)
Prototype Charts for Identifying Biaxial Phases
The systematic identification of uniaxial isomorphs has been extended to biaxial isomorphs. LUDO K. FREVEL, D e p a r t m e n t of C h e m i s t r y , T h e J o h n s H o p k i n s University, Baltimore M d . 21218 A n a l . C h e m . , 44, 1850 (1972)
The increase in chloride ions produced during the cyclization process was measured with both solid and liquid membrane electrodes. T h e method offers a rapid and relatively simple approach for the determination of reaction rate constants of this class of compounds. ADELBERT M. KNEVEL a n d P A U L F. KEHR, D e p a r t m e n t of Medicinal C h e m i s t r y a n d P h a r m a c o g n o s y , School of Phar m a c y a n d P h a r m a c a l Sciences, P u r d u e University, L a f a y e t t e , I n d . 47907 A n a l . C h e m . , 44, 1863(1972)
Detection of Nanogram Quantities of Hexachlorophene by Ultraviolet Liquid Chromatography A liquid chromatographic technique employing ultraviolet detection is offered as an alternate or complementary method to the present gas chromatographic electron capture de tection methods used for nanogram quantities of hexachloro phene. PETER J . PORCARO a n d PETER S H U B I A K , Research De p a r t m e n t , Givaudan Corporation, Clifton, N.J., 07014 A n a l . C h e m . , 44, 1865 (1972)
Hamming Type Codes Applied to Learning Machine Determinations of Molecular Formulas A classification scheme, based on the well-known self-correct ing Hamming code, has been developed. The use of this scheme could result in an improvement in the reliability of molecular formulas by machine intelligence. F. E. LYTLE, D e p a r t m e n t of C h e m i s t r y , P u r d u e University, Lafayette, I n d . 47907 A n a l . C h e m . , 44, 1867 (1972)
A N A L Y T I C A L CHEMISTRY, VOL. 4 4 , NO. 1 1 , SEPTEMBER 1 9 7 2
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17A
AC BRIEFS Titrimetric Determination of Ionic and Coordinated Azide Ion by Oxidation with Excess Nitrite Ion in Acid Solution
Simultaneous Microestimation of Choline and Acetylcholine by Gas Chromatography
A method, which gives an accurate analysis of relatively unreactive azide ion in coordination complexes and an es timation of the relative amounts of ionic and coordinated azide ion in the range 0.5—3.5 mmoles, is described.
This procedure utilizes derivatization of choline with propionyl chloride, followed b y jV-demethylation of both compounds with sodium benzenethiolate. Both compounds may be accurately determined in t h e presence of a large excess of the other.
W I L T O N R. BIGGS a n d RICHARD W. GAVER, D e p a r t m e n t of C h e m i s t r y , California State College, San J o s e , San J o s e , Calif. 95114
D. J. JENDEN, R. A. BOOTH, and MARGARET ROCH, De partment of Pharmacology, UCLA School of Medicine, Los Angeles, Calif. 90024
A n a l . C h e m . , 44, 1870 (1972)
Anal. Chem., 44, 1879 (1972)
Estimation of Trace Amounts of Chrysotile Asbestos by X-Ray Diffraction Sensitive X-ray diffraction techniques, using external and internal standards, were developed to detect trace quantities of chrysotile asbestos, with an accuracy ranging from 10% a t l O M g t o 2 % a t 100μg. A N T H O N Y L. RICKARDS, T u r n e r Brothers A s b e s t o s Co. L t d . , P.O. Box 40, R o c h d a l e , England A n a l . C h e m . , 44, 1872 (1972)
Gravimetric Analysis of Uranyl—Orthophosptiate Mixtures Uranyl and orthophosphate ions can be determined gravimetrically as U2O3P2O7. An accuracy of ± 0 . 2 % for uranyl, and ± 0 . 4 % for orthophosphate can be obtained.
Reaction of Nitrosamine with Fluorinated Anhydrides and Pyridine to Form Electron Capturing Derivatives A procedure, applicable for determination of mtrosoamines in biological samples, is described. JOHN B. BROOKS, CYNTHIA C. ALLEY, and ROY JONES, Center for Disease Control, Health Services and Mental Health Administration, Public Health Service, U.S. Depart ment of Health, Education, and Welfare, Atlanta, Ga. 30333 Anal. Chem., 44, 1881 (1972) Electrolytic Sample Preparation and Its Application to Atomic Absorption. Rapid Determination of Magnesium in Cast Iron By electrolytic dissolution and atomic absorption spectro photometry, magnesium is determined in cast iron in 1.5 minutes. T h e data vary from standard values by no more than 0.005% magnesium.
J . M. SCHAEKERS, A t o m i c Energy B o a r d , D e p a r t m e n t of Physical Metallurgy, Private BagX256, Pretoria, S o u t h Africa
A. H. JONES AND W. D. FRANCE, Jr., Chemistry Depart ment Rerearch Laboratories, General Motors Corporation, Warren, Mich. 48090
A n a l . C h e m . , 44, 1873(1972)
Anal. Chem., 44, 1884 (1972) Determination of Trace Amcunts of Selenium in Wastewaters by Carbon Rod Atomization
Acidimétrie Titration of Heavy Metal Acetates Substantially better results are obtained by addition of bromide ions when heavy metal acetates are titrated and differentiated from alkali and alkaline earth metal acetates in HOAc with HCIO, titrant. MARC G. M A N N E N S , Research Laboratories, Agfa-Gevaert N.V., M o r t s e l , B e l g i u m A n a l . C h e m . , 44, 1876 (1972)
A flameless atomic absorption technique for determining trace quantities of selenium in wastewaters has exhibited a sensitivity of 50 picograms following H N 0 3 - H C 1 0 4 di gestion, with a relative standard deviation of 6.8% in replicate analyses. R. B. BAIRD, SOLOUKID POURIAN, and S. M. GABRIELIAN, San Jose Creek Water Quality Laboratory, The County Sani tation Districts of Los Angeles County, 2101 Workman Mill Lane, Whittier, Calif. Anal. Chem., 44, 1887 (1972)
Determination of Scandium by Precipitation with Benzilic Acid Scandium is determined by precipitation with benzilic acid at p H 1.5-5.0. T h e scandium tribenzilate is ignited to Sc 2 0 3 for weighing. Yttrium, thorium, uranium, zirconium, and the rare earths interfere. MICHAEL H. M U L L I N a n d RICHARD Β. Η Α Η Ν , D e p a r t m e n t of C h e m i s t r y , Wayne State University, Detroit, M i c h . 48202 A n a l . C h e m . , 44, 1878 (1972)
Improved Gas Chromatographic Method for Field Measurement of Nitrous Oxide in Air and Water Using a 5A Molecular Sieve Trap N2O has been quantitatively determined at the p p b to ppm level with a standard deviation of ± 1 . 4 % for air samples and ± 1 . 7 % for water samples. JURGEN HAHN, Max-Planck-lnstitut Hahn-lnstitut), Mainz, West Germany
fur Chemie (Otto-
A n a l . C h e m . , 44, 1889(1972)
ANALYTICAL CHEMISTRY, VOL. 44, NO. 1 1 , SEPTEMBER 1972 ·
19A
AC BRIEFS Principles of Hot Plate Chromatography
Correspondence
Components with very close R F values were successfully separated from a mixture by hot plate chromatography. Trace components could also be detected. SRECKO TURINA, Institute for Material Investigations, University of Zagreb, Zagreb, Yugoslavia, and VJERA JAMNICKI, Pharmaceutical and Chemical Works "PLIVA," Zagreb, Yugoslavia
Determination of Chromatographic Resolution for Peaks of Vast Concentration Differences GLENN C. CARLE, Ames Research Center, NASA, Moffet Field, Calif. 94035 Anal. Chem., 44, 1905 (1972)
Anal. Chem., 44,1892 (1972) Study of Cobalt(lll) Complexes by Atomic Absorption Spectrometry. Effect of Ligands and Distribution of Atomic Cobalt in the Flame
Comments on Smoothing and Differentiation of Data by Simplified Least Square Procedure
Cobalt atomic absorption of cobalt(III) complexes in an a i r acetylene flame differs with various ligands and depends particularly on the coordinating atoms. Interfering effects can be overcome by the use of a high temperature flame. KITAO FUJIWARA, HIROKI HARAGUCHI, and KEIICHIRO FUWA, Department of Agricultural Chemistry, University of Tokyo, Tokyo, Japan 113
JEAN STEINER, YVES TERMONIA, and JULES DELTOUR, Laboratoire Central du Camira et Department de Physique et Chimie Physique, Faculté des Sciences Agronomiques, 5800 Gembloux, Belgium Anal. Chem., 44, 1906(1972)
Anal. Chem., 44,1895 (1972) Separation of T h o r i u m from Lanthanum and Other Elements by Cation Exchange Chromatography at Elevated T e m p e r a t u r e s Cation exchange distribution coefficients of T h and Zr increase faster with increasing temperature t h a n those of La. As a result, improved separations of T h from La, the rare earths, and other elements can be obtained by cation exchange chromatography at 50 °C using H O as eluting agent. F. W. E. STRELOW and A. J. GRICIUS, National Chemical Research Laboratory, Pretoria, Republic of South Africa Anal. Chem., 44, 1898 (1972) Determination of Lanthanum in Cobalt-Base Alloys by X-Ray Fluorescence Spectrometry A method for the determination of La (0.1-0.2%) in Co-base alloys is described. Factors giving t h e best spectrometric conditions were studied so t h a t a detection limit of 0.003% could be reached. F. J. HAFTKA, Union Carbide European Research Associates, Brussels, Belgium Anal. Chem., 44, 1900 (1972) Detection Limits in Analysis of Metals in Biological Materials by Laser Microprobe Optical Emission Spectrometry Detection limits for Li, Mg, Ca, Fe, Cu, Zn, Hg, and P b in biological material were determined by optical emission spectrometry, using a laser microprobe equipped with time differentiated photoelectric detection. The limits ranged for respective elements from 10 ~ 13 -2 X 10~ 1 5 g.
" T r a d i n g Rules" in Infrared Fourier Transform Spectroscopy PETER R. GRIFFITHS, Sadtler Research Laboratories Inc., 3316 Spring Garden St., Philadelphia, Pa. 19104 Anal. Chem., 44, 1909 (1972)
Rapid Atomic Absorption Determination of Silver and Copper by Sequential Atomization from a Graphite Rod R. D. REEVES, C. J. MOLNAR, and J. D. WINEFORDNER, Department of Chemistry, University of Florida, Gainesville Fla. 32601 Anal. Chem., 44, 1913(1972)
Molecular Design—Tetrachloroterephthaloyl Oligomers as Liquid Phases for Gas Chromatography STANLEY H. LANGER, Department of Chemical Engineering, University of Wisconsin, Madison, Wis. 53706 Anal. Chem., 44, 1915 (1972)
Use of Large Overpotentials in Galvanostatic Measurements
WILLIAM J. TREYTL, JAMES B. ORENBERG, KENNETH W. MARICH, ARTHUR J. SAFFIR, AND DAVID GLICK, Division of Histochemistry, Department of Pathology, Stanford University Medical School, Stanford, Calif. 94305
FLOYD H. BEYERLEIN and RICHARD S. NICHOLSON, Chemistry Department, Michigan State University, East Lansing, Mich. 48823
Anal. Chem., 44, 1903 (1972)
Anal. Chem., 44, 1917 (1972)
ANALYTICAL CHEMISTRY, VOL. 44, NO. 11, SEPTEMBER 1972
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A C BRIEFS
Aids for A n a l y t i c a l Chemists A Geiger-Muller Counter Designed to Measure Reproducibly Activities Retained on Resin Columns M. HEURTEBISE and J. A. LUBKOWITZ, Departmento de Tecnologia Nuclear, Instituto Venezolano de Investigaciones Cientificas, Apartado 1827, Caracas, Venezuela Anal. Chem., 44, 1918 (1972)
ANALYZE DRUGS IN MINUTES with SORVALli
CENTRI-CHROM A Thermo-Barometer CLAUDE R. REED, Texaco Inc., Beacon, N.Y. 12508 Anal. Chem., 44, 1921 (1972)
New, Simple Windowless Cell for Front-Surface Fluorometry J. A. McHARD and J. D. WINEFORDNER, Department of Chemistry, University of Florida, Gainesville, Fla. 32601 Anal. Chem., 44, 1922 (1972)
Triac Switching Circuitry for Eliminating Interfering Transients in Digital Logic Automated Systems E. S. IRACKI, M. B. DENTON, and H. V. MALMSTADT, School of Chemical Sciences, Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, III. 61801 Anal. Chem., 44, 1924 (1972)
Sorvall CENTRI-CHROM is the last word in rapid centrifugal chromatography systems. It provides chromatograms of unusually accurate resolution and reproducibility. CENTRI-CHROM will help you identify components of drugs with surprising speed — usually in about 6 to 15 minutes. And it will reveal sample components that other methods may not even "suspect". Operating in the Sorvall GLC-1 Centrifuge, CENTRI-CHROM is complementary to other sys tems. It's remarkably easy to operate. Compara tively large amounts of a sample may be used: 5 μ\ or 50 μ I. Components elute semi-preparatively. If you are involved in the analysis of drugs and other substances, you owe it to yourself to ana lyze all the facts about CENTRI-CHROM. They're yours without obligation. Write or phone us—the sooner the better, if you want fast results.
IVANSORVALLINC. NORWALK · CONNECTICUT · 0 6 B 5 6
Phone (203) 847-2491 Ask for Bulletin
AC-9ADA
Typical examples of CENTRI-CHROM separations Synthetic Cannabinoids
Technique for Chemical Ionization Operation of a CEC 21-110B Mass Spectrometer T. J ODIORNE and D. M. DESIDERIO, Institute for Lipid Research and Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77025 Anal. Chem., 44, 1925 (1972)
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