NEW PRODUCTS FOR ANALYSTS Equipment, Apparatus, Instruments, Reagents, Materials Aromatic Hydrocarbon Detector
A portable, lightweight aromatic hydrocarbon detector is available from the Mine Safety Appliances Co. The instru ment has separate graduations for benzene, toluene, and xy lene. In the detector tube, a stain increases in length in di rect relation to the aromatic concentration. The cylindrical scale is easily adjusted to bring the zero setting in line with the reagent level in the detector tube. Because the detector tubes can be filled in the field, stability of the indi cating material is assured. Twelve tubes can be filled at one time for convenience, and these can be stored for 2 or 3 weeks without loss of sensitivity. Included in the instrument as sembly are a color scale, tube rack, mixing bottle, mandrel, 12 rubber tube caps, and a kit for 12 separate tests. The kit contains two vials of granular material, 12 empty detector bottles, and glass cloth swatches. The instrument is sup plied in a leather carrying case with shoulder strap. 1 Vacuum Dryers
Construction changes in the vacuum shelf dryers offered by the F. J. Stokes Machine Co. permit improved low-cost dry ing at absolute pressures in the low micron range. Dryer shelves with internal baffles are arranged to provide uniform heat throughout the entire shelf area. The jacketed con struction of the top surface of the dryer prevents condensa tion of the vapors passing toward the vacuum connection. The lower section of the dryer is fitted with a drain gutter and outlet to permit cleaning of the unit without spillage. The door of the Stokes No. 138 chamber has been changed from cast iron to steel. The Β chamber now has two 6-inch sight glasses, while the Η and J have three 9-inch glasses in stead of the usual 4.5-inch ports. A swivel spotlight, attached to the dryer door, permits close observation of the material during the drying process. This spotlight can be quickly and easily moved to any one of the large glass ports in the door.
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Swinging eyebolt clamps and handwheels provide easy sealing of the chamber. Specially shaped extruded gaskets fitted into machined grooves in the dryer doors assure a posi tive seal. The dryers are available in seven chamber sizes, with shelf spacing to suit specific requirements. When neces sary, special metals can be furnished, together with metalsprayed interiors. Steam, hot water, or oil can be used for maintaining various drying temperatures. 2 Plastic Bottles
Polyethylene bottles manufactured by Plax Corp. are now being used by Beckman Instruments, Inc., as containers for standard buffer solutions. These solutions are available in pH 4.00, 7.00, and 10.00. Each bottle of buffer solution is heat-sealed with a film of polyethylene. In opening a new bottle, the user merely removes the bottle cap, punctures the seal, and squeezes the flexible container. Breakage of the bottles as a result of impact or freezing is eliminated. 3 Mass Spectrometer
A new model has been added to the line of mass spectrom eters manufactured by Consolidated Engineering Corp. This ^ — _,„, instrument, Model 21-401, is a dual-purpose mass spectrometer designed for the analysis of mixtures of gases and light liquids, as well as for the determination of ratios of stable isotopes. I t will fill a particular need in laboratories having mod erate analytical loads of a routine nature and will be valuable in research applica tions involving m i x t u r e analysis and stable isotope tracer techniques. The instrument does not require refrigerants, such as liquid nitrogen. Numerous automatic devices serve to minimize
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operator errors and thus reduce the time required to carry out an analysis. For mixture analysis, the instrument has a mass range of 2 to 100, with automatic scanning and record ing of spectra from mass 12 to 100. About 15 or more com plete runs can be made in an 8-hour shift. The spectrum is recorded on a strip-chart recorder, and automatic attenuation of peak magnitudes provides a dynamic recording range of 300,000 t o i . In isotope-ratio work, the ratio is not only obtained directly by an automatic null balancing method but is also recorded. Within sensitivity limitations, any ratio from 0 to 1 can be measured. The first three decimal places are obtained from decade dials; the last three from the pen-and-ink record. The conversion from mixture analysis to isotope-ratio meas urements can be accomplished in a matter of minutes. 4 High-Purity Mereury Bethlehem Apparatus Co. is offering mercury specifically for use in instruments requiring a high degree of accuracy. A flexible dispensing tip delivers this mercury directly from an unbreak able Expound polyethylene bottle. Transfer containers, spillage, and exposure of the mercury to impuri ties in the air are thus eliminated. This mercury is said to be superior to standard reagent mercury, remaining bright indefinitely in storage and in instruments. The product, in larger containers, is suitable for use in ma nometers, polarographs, cathode cells, and other instruments. 5 Water Purification Recently developed by Enley Products, Inc., the Demon demineralizer produces pure, demineralized water for only a few cents per gallon in most areas. This unit has been de veloped for small-quantity users, for whom the usual large equipment would be impractical. Merely by attaching the unit to a regular water tap, the user can produce up to 120 gallons of pure water per cartridge. The demineralizer has an allowable flow rate of up to 30 gallons per hour. The unit consists of a replaceable plastic cartridge contain ing resins whose color progressively changes from blue to yellow as the resins become exhausted. The cartridges are removed and replaced when the exhaustion line reaches the bottom. Ionic contaminants are removed from solution bv the
mixture of anion and cation exchangers*, Fiberglas filters help to trap physical impurities. Even if the concentration of dissolved salts in a particular water supply is high, the unit can reduce this concentration to less than 0.1 p.p.m. A complete unit costs $14.95, and the replaceable cartridges cost $5.50 each, with a $1.00 credit allowed for each exhausted cartridge. & Stopcock Adapters Three sizes of stopcock adapters—small, medium, and large—to cover the full range of laboratory stopcocks have recently been introduced by the Emil Greiner Co. The small size adapter covers the range of 2- to 4-mm. stopcocks; the medium size covers 6 to 8 mm.; and the large size, 10 to 15 mm. These adapters are designed for laboratory workers who require pressure stopcocks for burets, gas sampling, measuring apparatus, and other applications. Manufactured com pletely of corrosion-resistant materials, they eliminate the annoyance of leaking stopcocks and the high cost of special pressure stopcocks. 7 Moisture Determinations The Model 276-S offered by Harry W. Dietert Co. may be used for drying a wide range of samples. The unit is equipped with a thermostat having a range of 150° to 300° F. The temperature may be controlled to within 7° F. of the selected temperature. The heat ing element is of heavy Nichrome wire. The outer housing is well in sulated from the heating element, thus ensuring a relatively cool outer surface. Sample pans, either 1 or 2 inches in depth, may be used. Unlike pre vious models, this unit is equipped with pans made of stainless steel rather than aluminum. As many as three samples contained in a 50 X 25 mm. dish may be dried at one time. The unit's efficient ventilation accelerates the drying process. 8 5f©racje Cabinet A new storage cabinet for radioactive samples has beeu de veloped by Nuclear Instrument and Chemical Corp. A major feature of this cabinet, Model N4, is its provision for replacing sample holders or the sample holding tray in case of con-
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CHEMISTRY
Use this handy return card to save yourself time. It will bring information of use to chemists and engi neers in laboratory, pilot plant, and production. The items listed in this special section have been selected by the editors of ANALYTI CAL CHEMISTRY for their value and timeliness in helping you to keep abreast of the latest developments in the field.
