PIERCE CHEMICAL COMPANY

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NEW CHEMICALS GC-Assayed Reagents Twenty-five Baker Analyzed reagent solvents are now provided with a gc assay on the label which states the purity of solvent and ensures extremely low levels of interfering background. A minimum assay specification of 99.0% has been established for 23 of these reagents; and for acetone and methanol, a minimum of 99.5% has been adopted. The other 23 solvents are acetonitrile, aniline, benzene, benzyl alcohol, 1-butanol, carbon disulfide, carbon tetrachloride, cyclohexane, 1,2dichloroethane, diethylamine, dimethylformamide, 1,4-dioxane, ether, methylene chloride, methyl ethyl ketone, 2methyl-1-propanol, 1-propanol, 2-propanol, isopropyl ether, pyridine, tetrachloroethylene, tetrahydrofuran, and trichloroethylene. In addition, another 15 reagents (Instra-Analyzed) are further purified to meet both spectrophotometric needs and also to meet the 99% puritv by gc assav. J. T. Baker Chemical Co. 201859-2151 501

emitted as a gas at a rate that is temperature-dependent. Knowing this rate, which is certified by NBS, permits users of gaseous pollution measuring equipment to calibrate their instruments. SRM 1625 costs S50 per tube. Tubes are accompanied by a certificate of analysis that states the tube's rate in micrograms of S0 2 per min for integral degrees from 20°" to 30°C. National Bureau of Standards, Washington, D. C. 20234. 301-921-2691

Kits for Phosphorus and Calcium A calcium Rapid Stat Kit for the manual colorimetric determination of calcium in serum and other fluids contains necessary reagents and standards for 120 tests." Kits cost $16 each; 10 kits, $11.50 each. A similar kit for phosphorus which claims a sensitivity to less than 1 ppm with a very small sample costs the same as the calcium kit. Pierce Chemical Co. 815-968-0747 504 Gc Standards C 42 tetracontane and C 44 tetratetracontane are available at 99% purity for use as internal standards for analytical

gas chromatographic determinations of organic compounds. Also available at 95% purity are methyl eicosapentaenoate and methyl docosahexaenoate, compounds believed to play an important role in the biosynthesis of prostaglandins. Applied Science Laboratories, Inc. 814-238-2406 505 Nmr Shift Reagents Two new nmr shift reagents, Euroshift-F and Prashift-F, are partially fluorinated chelates, consisting of the lathanides complexed with heptafluorodimethyloctane-dione [H(fod)]. Ad : vantages include higher solubility in CCI4 and the production of dramatic paramagnetic 1 H nmr shifts in the opposite sign to each other, thereby producing excellent complementary performance. Euroshift-F costs $25/g and Prashift-F, $100/5 g. Pierce Chemical Co. 815-968-0747 . 506 Thin Metal Foils Nickel foil, pinhole free, at 0.001 mm (0.00004 in.) and copper foil 0.0015 mm in pieces 50 X 50 mm are available. Other metals available in minimum foil thicknesses are Cu, Au, Ni, Pd, Pt, Rh, and Ag. Other high purity metal materials are also available. Goodfellow Metals Ltd. Esher 65391 507

Sodium Zirconyl Glycolate Sodium zirconyl glycolate, a negative stain useful in electron microscopy work is offered as a microfiltered O.lAf solution sealed under nitrogen gas in 10-ml ampuls for direct use in preparing specimens. The compound may be used over a wide pH range with different buffers and resists precipitation in the presence of high concentrations of salts. Polvseiences, Inc. 215-3436484 " 502

KEEP G.C. COLUMNS AT PEAK EFFICIENCY with α fast injection of a ®

Nmr Shift Reagents E u ( D P M ) 3 and P r ( D P M ) 3 chelates are available for use as shift reagents in nmr work. The reagents are said to displace interfering resonance lines thereby simplifying certain compounds to first-order interprétable spectra. These specially purified chelates contain no water. They are priced at $18 per gram and $320 per gram. Apache Chemical, Inc. 815-877-7858 503 Sulfur Dioxide Permeation Tube A new Standard Reference Material makes possible the accurate determination of sulfur dioxide content of air. This SRM consists of a plastic tube filled with liquid sulfur dioxide, which permeates the walls of the tube and is

Inject a few microliters of Silyl-8®between runs on your G.C. and watch that base line settle d o w n ! Or, if a sample is going to pot on your column, no need to shut down your instrument several hours to condition the column; just inject Silyl-8 and in less than 5 minutes you're ready to go again. Silyl-8 is 100% active and is composed of three power­ ful silylating reagents. It acts by blocking active sites that have developed on your pack­ ing. Economical, t o o ; each 1 ml hypovial is sufficient for 20 to 70 shots averaging less than 2 cents per shot. Useful for all types of columns except those with Η-bonding phases. 38014 SILYL-8 GLC Column Conditioner $10/pkg 12 χ 1 ml vials

Our silylation reagents are known the world over for their purity, efficiency and conven­ ience. The ready for use T R I - S I L ® f o r m u l a ­ tions rapidly produce volatile and thermally stable derivatives for gas phase analyses in simple one step procedures. Our free 60 page booklet Handbook of Silylation des­ cribes these and other reagents, solvents and standards, lists methods and references and provides numerous suggestions and practical ideas. If you don't have a copy we'll be glad to send you one.

PIERCE CHEMICAL COMPANY P. O. Box 117 Re PHONE B15j96e-07J

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ANALYTICAL CHEMISTRY, VOL. 43, NO. 7, JUNE 1971

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