Variscan™ that lets you se Variscan permits you to detect and analyze compounds tr 210nm
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Variscan detector, front center, can be used with liquid chromatograph models 4000, 4100 and 4200 (shown here).
New Products Accessories Ultraviolet Instruments: Accessories Two new accessories for P-E UV spectrophotometers include a magnetic tape comparator which corrects for uneven base line variations in recording difference spectra or derivative spectra and a new rapid-mixing cell for stopped-flow reactions. The latter facilitates the study of reaction mechanisms and permits the observance of short-lived intermediate compounds. Perkin-Elmer 417
PDP-11 Minicomputer: Memory Model 11 is said to be the fastest add-on memory available for DEC's PDP-11 Series minicomputers. The new units use a 650-nsec field-proven core memory system; data access time is 250 nsec. Core memory storage can be up to a full 124K words. Fabri-Tek, Inc. 421
C o m p a r e d to Variscan, other LC detectors are almost blind. They operate at only one or a few wavelengths.
Variscan can be used with gradient elution and is compatible with a wide range of chromatographically useful solvents.
Variscan operates over the entire UV-Vis spectral region, from 210 to 780 nm, with no sacrifice in efficiency. At the turn of a dial you can set Variscan at the maximum absorption wavelength of virtually any compound.
Minimum detectable quantities are nanogram amounts. Cell volume is small, only 8 microliters, so that peak spreading is minimized; and the cell p a t h is long, 1 centimeter, so that response to low concentrations is increased.
And whenever you wish, you can quickly stop flow, push a button and obtain absorption spectra of individual peaks in your chromatogram.
T h e Variscan LC detector is basically a unique Varian UV-Vis spectrophotometer. The spectrophotometer flow cells are a matched pair.
Spectrophotometers: Thermal Programmer A plug-in module provides precise temperature control and linear temperature scans for company spectrophotometric systems. The Model 2427 permits four samples to be thermoelectrically heated or cooled to a preset temperature, or scanned at one of three rates, while displaying sample temperature. Gilford Instrument Laboratories, Inc. 423
Nuclear Counting: Sample Changer
IR Spectrophotometer: Gas Cell
A new automatic sample changer accepts as many as 50 samples on planchettes up to 2 in. in diameter. Samples may be filters, solids, or evaporated liquids. The unit can be used with gas flow proportional counters, end window Geiger-Mueller tubes, scintillation counters, and solid state detectors. $9000. Nuclear Measurements Corp. 425
A variable-path 20-m gas cell can be adapted to the company's infrared spectrophotometers for vapor-phase or gas analysis in the low ppm range. The cell has optical pathlengths of 0.75 to 21.75 m in steps of 1.5 m. $2300. Beckman Instruments, Inc. 420
TLC: Applicator For more information on listed items, circle the appropriate numbers on one of our Readers' Service Cards
1148 A · ANALYTICAL CHEMISTRY, VOL. 45, NO. 13, NOVEMBER 1973
A thin-layer chromatography applicator will spot up to 19 different samples in a single motion. For preparative work, the spotting pipets can be used in making 37 spots. Analabs 424
îe LC detector ne hell of a lot more sorb at any UV-Vis wavelength from 210 nm to 780 nm. 550 L_
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ν VIS Water-jacketed, they maintain stable temperature equilibrium between the cell and the solvent, even with flow programming. T h e carefully matched optical paths of the spectrophotometer also minimize noise and drift. Overall system noise is s>±5 χ 10 -4 absorbance unit from 210 to 780 nm; drift is lower than 10 2 absorbance unit/hour—performance specifications which ensure that you will see more with Variscan than with any other L C detector. L C is no longer detector-limited.
N o w it is possible to detect and analyze a m u c h broader range of compounds. Pardon our French, b u t you really can see one hell of a lot more with Variscan.
For complete details see your Varian representative or write: Varian Instrument Division, 611 Hansen Way, Box D-070, Palo Alto, California 94303.
varian instruments Brand names: ANASPECT™ · CARY® · M A T · VARIAN® VARIAN AEROGRAPH® · V A R I A N TECHTRON CIRCLE 208 ON READER SERVICE CARD
Infrared Spectrometers: Reflection A new multiple internal reflection accessory for all company infrared spectrophotometers consists of a basic optical unit and a universal sample holder. Three crystal positions (30°, 45°, and 60°) are offered as well as three different angled crystals for user flexibility. Perkin-Elmer Corp. 422
Digital Printer Techtron Model 36 digital printer can be used with Techtron digital spec trophotometers, both atomic absorp tion and UV-VIS spectrophotometers. With the instrument, readout is re corded on a paper tape at a maxi mum rate of one line every 2 sec with 14 columns for sample identification and analytical data. $1850. Varian 419
Chemicals Radioactive Isotope Gadolinium-153 with a 242-day halflife and principle energy of 100 keV can be supplied in bulk as GdClg in liVHCL solution: concentration, >50 mCi/ml; radiopurity, 99.99%. Sources up to several curies can also be pre pared. Atomic Energy of Canada, Ltd. 429
Mass Spectrometry: Ion Source A field desorption ion source for mass spectrometry incorporates two addi tional ion generation methods: field ionization and electron impact. Heart of the FD source is the ion emitter: a wire covered with microneedles of carbon. This emitter can be dipped into a solution and inserted into the combined ion source through a vacu um lock. Sample molecules absorbed on the surface are then ionized in a strong electrical field but at lower temperature than usually required for vaporization. This system is especial ly useful as a tool in such areas as studies of drug or pesticide metabo lites, antibiotic studies, and cancer research. Varian 418 ANALYTICAL CHEMISTRY, VOL. 45, NO. 13, NOVEMBER 1973 · 1149 A
