News
Our new HPLC Columns ore well pocked!
Analytical Chemistry at Work
Guaranteed peak symmetry and minimum plates per meter doubly assure you of optimum column performance. A completely new line of "stateof the-art" packed columns for high pressure liquid chromatography is now available in the U.S. and Canada from Rheodyne. All columns are 4.6 mm ID χ 25 cm long. Each column is tested and supplied with its own chromatogram. Currently six columns are available over a price range of $180 to $240. The table below showing column performance specifications and typical test conditions offers an excellent argument for the addition of these columns to your HPLC equipment. TYPEMN Particle
SI-100· 5 μΓη
Min. plates per meter
36,000
Max. peak asymmetry
1 6
Solvent 2ffi. ml/mm Pressure, pst
NH 2 , 0 μχη 14,000 1 6
DIOL 1 0 ltm
" ..
RP-8 5 μΓη
26.000 1 6
hexane
hexane
hexane
^tonltrife"
2.0
2.0
2.0
2.0
1640
280
280
Test nitronitronitrosubstance benzene benzene benzene 'available in 10 μπι particle size also, "under evaluation
Portable S y s t e m for Clinical and Environmental Determinations A portable microprocessor-con trolled centrifugal fast analyzer (CFA) has been developed and demonstrated by a group of scientists at Oak Ridge National Laboratory. With this in strument, the composition of up to 16 different chemical and biochemical samples can be determined simulta neously within seconds. A prototype of the instrument was shown at the Ninth Annual Symposium on Ad vanced Analytical Concepts for the Clinical Laboratory held in March of this year. The centrifuge, which rotates at speeds up to 4000 rpm, forms the basis of this instrument as well as its prede cessor developed in 1968. Measure ments are made of the optical proper ties of material such as their transmis sion, fluorescence, light scattering, or luminescence. Carried out simulta neously at 17 different locations on the rotor, these measurements are compared with the known optical properties of reference materials to provide the determinations. A battery pack or 110-V alternating current provides power. T h e self-con
tained microprocessor controls the an alytical functions and provides versa tility in operating conditions, as well as acquiring and analyzing the data. Analytical options include the deter mination of reaction rates by linear re gression analysis. Applications of the instrument in mobile laboratories, in small clinics, or even at a patient's bedside are sug gested. Possibilities also exist for its use in assaying environmental pollu tants such as phosphate, silica, and ammonia. Because of its capabilities in determining reaction rates, the sys tem could be used in research investi gations of fast chemical and biochemi cal reactions. Routine clinical measurements, such as glucose, protein, or uric acid, as well as enzyme activity assays, can be handled with this system with im proved performance over earlier mod els of the miniature CFA. Work con tinues to provide computer software enabling the instrument to supply op tical measurements at multiple wave lengths during a single analysis, and for electronic self-checking by the computer. The research on this system is spon sored by the Energy Research and De velopment Administration, EPA, NASA, and the National Institutes of General Medical Sciences. The many people who contributed to the devel opment include J. E. Mrochek, C. A.
3000
diethyl phthalate
Made by Brownlee Labs, the columns are guaranteed by both Brownlee and Rheodyne. Column packings are LiChrosorb (a registered T.M. of E. Merck Darmstadt Germany). For More Information. A detailed technical brochure is available for the asking. Address Rheodyne, Inc., 2809 Tenth Street, Berkeley, CA 94710. For even faster service, phone (415) 548 5374.
RHCODSJNC
John E. Mrochek holds the rotor housing of the portable centrifugal fast ana lyzer. The instrument is 18 X 11 X 12 in. in size and weighs only 55 lb. An in corporated microprocessor controls the drive system, rotor speed, and clutchbrake and automatically synchronizes these functions with data acquisition. Other analyzer functions under microprocessor control include the selection of preamplifier gain, transmission filters, and primary and secondary filters for fluorescence
CIRCLE 177 O N READER SERVICE CARD 7 0 6 A · ANALYTICAL CHEMISTRY, VOL. 4 9 , NO. 8, JULY 1977
