MATHESON GAS MIXTURES for Instrument Calibration
In addition to all of the cali bration mixtures, Matheson supplies custom gas mixtures of every type, including radio active gas mixtures. Extreme ly close tolerances on specifi cations can be held. Exact analysis of mixtures is avail able. Here are a few of the instruments for which calibra tion mixtures are offered: Oxygen Analyzers Gas Chromatography Infra Red Mass Spectrometer P r a c t i c a l l y a n y m i x t u r e of t h e 85 g a s e s listed in t h e M a t h e son C o m p r e s s e d G a s C a t a l o g can b e supplied, t o y o u r speci fications. T h i s C a t a l o g con tains information on t h e w o r l d ' s m o s t c o m p l e t e line of compressed gases, and gas regulating a n d handling equip ment. Write for catalog
THE MATHESON COMPANY, INC. East R u t h e r f o r d , N . J.; Joliet, 111.; N e w a r k , Calif. Matheson of Canada, Ltd. Whitby, Ontario
NEW PRODUCTS
one of a series
Preparative Electrophoresis Continuous free-flow electrophoretic separator features a "free-flowing" buffer film in a glass chamber where separation takes place—no paper, starch, glass beads, or other carrier is used. Advantages include : a through put rate of 10-20 grams dry weight per day, operating voltages to 3000V/cm.; separations of molecular weights which cannot be accommodated on other elec trophoresis systems including viruses, dissolved protein fibers, cell suspen sions, etc., 100% recovery of sample; elimination of diffusion problems, no interaction between carrier and sample ; adjustable buffer blow, and up to 96 collection tubes. Literature available. Elphor Model " F F " Brinkmann In struments, Inc., 115 Cutter Mill Rd., Great Neck, L. Ι., Ν . Υ. 420
A New Concept in Ion Exchangers
CM-Sephadex® I n t r o d u c t i o n of ionic groups into SEPHADEX, a hydrophilic
insoluble
product derived from cross-linking the polysaccharide, dextran, makes possi ble an entirely new series of ion e x c h a n g e r s . T h e S E P H A D E X ion ex
changers have • High capacity • Low nonspecific adsorption SEPHADEX ion exchangers make possi ble the purification, separation and fractionation of a wide range of low molecular weight, complex organic compounds, proteins, and related ni trogenous substances with high yields. A diversity of types, both anionic and cationic, are available to meet specific requirements. Have you investigated—
Five-inch diameter detectors for alpha and beta counting are offered as part of the Lowbeta and Lowbeta/matic Systems. The latter systems utilize an automatic sample changer that holds up to 60 samples, 4V2 inches in diameter or smaller. Sharp Lab oratories, Inc., Box 2078, La Jolla, Calif. 421 Electronegative Gas Detector Developed to detect and measure the concentration of sulfur hexafluoride, a new instrument can also detect and measure other electronegative gases. The instrument will detect concentra tions of gases as low as one part in 10 million parts of air. In operation, the instrument takes in air suspected of containing the gas of interest, floods it with electrons, and sorts out this gas by its extra tendency to attract and cap ture the electrons. The negative ions thus formed are less mobile than others normally present, and will lag behind when the ions are electrically attracted to a positive terminal. This time de lay is measured and displayed by the appropriate instrumentation. Westinghouse Research Center, Scientific Equipment Dept., Pittsburgh 35, Pa. 422
CM-Sephadex Active group I carboxymethyl character I cationic, weakly acidic capacity I 4-5 meq/g CM-SEPHADEX is prepared in two forms:
C-25, which is highly effective for sepa rating low molecular weight, complex organic substances, and C-50, which has a far greater binding capacity than C-25 for large size molecules—particu larly useful for purification of proteins, enzymes, and related nitrogenous compounds. This product is available in the follow ing sieve fractions: Coarse, Medium, and Fine. PHARMACIA FINE CHEMICALS, INC. 501 FIFTH AVENUE NEW YORK 17, NEW YORK AC
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Send me information on SEPHADEX Ion Exchangers.
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Circle No. 184 on Readers' Service Card VOL. 3 4 , N O . 1 2 , NOVEMBER 1 9 6 2
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