NEW PRODUCTS
Gas liquéfier produces small quantities of cryogenic fluids. The liquéfier is a small counterflow heat exchanger which uses compressed gas from a conventional high-pressure cylinder. The amount of cryogenic fluid produced and the time required to produce it varies with the gas used and the pressure of the gas. With a cylinder of gaseous argon at 2600 p.s.i., 3 cc. of liquid argon can be produced in 5 minutes. Linde Division, Union Carbide Corp., 270 Park Ave., New York, Ν. Υ. 10017 412 Germanium Detectors Lithium drifted germanium detectors are available in this series in five stand ard sizes, complete with vacuum cryostat, liquid nitrogen chamber, and a 1-liter-per-second ion pump. Guaran teed resolution for these detectors is 4 k.e.v. A compatible series of low-noise preamplifiers and amplifier-coincidence modules is also available for high-reso lution applications in nuclear spectrom etry. Technical Measurement Corp., 441 Washington Ave., North Haven, Conn. 06473 413 Chromatography Column New Sephadex laboratory columns for gel filtration and ion exchange chro matography with aqueous systems are designed to serve as one basic column system for both descending and ascend ing chromatography. The initial col umn is available as a descending sys tem, either jacketed or unjacketed, but can be quickly converted to an ascend ing system by removing both end pieces of the column and replacing them with two upward flow adaptors. Pharmacia Fine Chemicals, Inc., 800 Centennial Ave., Piscataway, N. J. 08854 414
Current Detector
Filter
Membranes
Streaming current detector is an al ternating streaming current device in a rugged, portable form for determining the polarity and quantity related to the electrical charge density on colloidal particles. The instrument provides a measurement of streaming current rather than potential. A valveless posi tive displacement pump is the energy coupler of the system. Waters Associ ates Inc., 61 Fountain St., Framingham, Mass. 415
New filter membranes permit filtra tion of any corrosive liquid or gas at temperatures as high as 650° F. or down to —450° F. These membranes are made of Zitex, a new physical form of Teflon/Halon. They are character ized by their chemical inertness, heat resistance, low temperature flexibility, and nonadhesive quality. Six grades are available in diameters ranging from 75 to 150 mm. Chemplast, Inc., 150 Dey Rd., Wayne, N. J. 07470 416
Read Number-Average Molecular weight in Minutes For speed and convenience in determining molecular weight (5,000 to 500,000 MW), you'll find it hard to steal a march on Hallikainen's Model 1361 Automatic Osmometer. Within 10 minutes of sample injection, osmotic pressure appears on a large digital counter within 0.01-cm accuracy over a 10-cm range. You can read four concentrations and calculate number-average molecular weight in less than an hour. With a simple exchange of sample inlet funnels, Model 1361 can be used for both low (35°C) and high (135°C) temperature work. No need to invest in separate instruments.
4.76 7.53 2.92 5.03 8.14
The entire unit, including built-in chart recorder, occupies a trim 12x 15 χ 13-inch cabinet. For further information, write today for the informative four-page brochure.
HALLIKAINEN Instruments
750 National Court, Richmond, Cal. 94804 Respondents living outside North America, South America, and Japan are invited to address their inquiries to: Hallikainen Instruments Ltd., Blackwall Lane, Greenwich, London SE10, England. Circle No. 167 an Headers' Service Card V O L . 3 8 , N O . 9 , AUGUST 1 9 6 6
109
A
