New pump brings new precision to chromatography
NEW PRODUCTS
All Scott Research Gas Mixtures Have a Guaranteed Analysis . . .
Direct-reading laboratory turbidimeter measures turbidity from trace particles as low as 0.005 Jackson turbidity units to highly turbid waste sludge. The Model 2100 operates on the principle of measuring scattered light. Turbidity ranges are selected by rotating a range-change turret on top of the instrument which controls the amount of light passed from sample cell to the photomultiplier. Hach Chemical Co., Ames, Iowa 421 Chromatographers have been waiting years for this pump —a chemically-inert system that produces a constant, unperturbed flow at pressures up to 500 psi. The smooth flow enhances resolution and reduces detector noise: And the pump will handle any solvent because only glass, Teflon and Kel-F touch the stream. To eliminate irregular flow caused by back leakage, the pump uses sliding valves instead of the usual ballcheck valves. And to prevent reverse surges when operating into highpressure lines, each pump cylinder is pre-pressurized before the outlet valve opens. The pump's pistons are driven through gears by a synchronous motor, so that flow rates can be reproduced with the accuracy of an electric clock. A front-panel gear shift selects six precise flow rates from 2.4 to120ml/hr. Chromatronix also makes chemically-inert columns, fittings, and control valves—designed without mixing cavities to increase resolution.
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CHROMATRONIX I N C O R P O R A T E D 2743 Eighth Street, Berkeley, Calif. 94710 Phone (415) 841-7221.
in other words our gases are standard gases Your verification of the analysis is eliminated, t h u s saving time and money. Scott Research gas mixtures are made to order in cylinders containing 10 t o 200 cubic feet, 1 t o 20 trace or minor components in p a r t s per billion to percent concentrations. T h e " m a k e " tolerance is ± 1 0 % a n d analysis accuracies vary from ± 5 % t o ± 1 % of each trace component value depending on your requirements. W e purify m a n y gases for special applications, including use as zero gases a n d as major components of calibration standards. Our pure air with total hydrocarbon content less t h a n 0.1 p p m carbon is an example. A t Scott Research we have the necessary experience t o help you. For further information, call or write. Remember—all Scott Research gas mixtures, complicated or simple, have a guaranteed analysis.
Thermoelectric Dew Point Hygrometer A miniature dew point hygrometer is the heart of the Model 137-M1-ŒC dew point and temperature sensor. The instrument utilizes a copper-constantan thermocouple to measure the temperature of an optically-controlled, thermoelectrically cooled, gold plated mirror at the dew point. A radiation-shielded thermocouple measures the ambient air temperature; Cambridge Systems, Inc., 50 Hunt St., Newton, Mass. 02158 422 Automatic Carbohydrate Analyzer A high-pressure liquid-chromatography system to separate and measure many types of carbohydrates present in natural fluids was designed to automatically inject and analyze a sample containing dissolved sugars and simultaneously to display the results on a strip-chart recorder. As many as 30 compounds have been separated from a normal urine sample during a run of several hours. The sample bearing the separated carbohydrates is treated with concentrated sulfuric acid and phenol within the analyzer to develop a colored solution whose optical density is used as a measure of the amount of each compound present. The unit incorporates a dual-wavelength flow colorimeter which can be used for general laboratory work. Office of Industrial Cooperation, Oak Ridge National Laboratory, P. O. Box X, Oak Ridge, Tenn.
SCOTT RESEARCH LABORATORIES, INC. (215) 249-3526 P.O. Box 66, Dept. D, Perkasie, Penna. 18944 Circle No. 140 on Readers' Service Card
Circle No. 56 on Readers' Service Card VOL.
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