Required reading for better Chromatographic separations... SEQUENTIAL ANALYSIS •vlWnPCHROMAT«*AmY
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AN INTRODUCTION TO
HIGH-SPEED LIQUID CHROMATOGRAPHY
WHAT LIQUID CHROMATOGRAPHY CAN DO FOR YOU
MONITOR AND CONTROL OF CHROMATOGRAPHIC COLUMNS USING THE R-400 SERIES REFRACTOMETER
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Consider Waters' library of liquid chromatography information your resource for solving separations problems. We've got factual, concise, and help ful monographs on a wide variety of topics. They are yours for the asking. Send for our complete Applications Index today. (If your separations problem is more pressing, give us a call and we'll do our best to help you)
WATERS ASSOCIATES 61 Fountain Street Framingham, Massachusetts THE LIQUID CHROMATOGRAPHY PEOPLE CIRCLE 2 1 8 O N READER SERVICE CARD
New Chemicals Ausria-125 for hepatitis detection is a newly licensed diagnostic test. In the Ausria test of a blood sample, which ig,a radioimmunoassay process, a radioactive tracer will link with hepatitis-associated antigen if it is present. A radioactivity counter then identifies and measures the level of antigen present. Abbott. 312688-3930 437
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Alkyl-8 family of reagents is convenient for the formation of methyl, ethyl, propyl, π-butyl, and t-butyl esters of fatty acids for gc analysis. The dimethylformamide dialkyl acetal reagents are stable at room temperature and packaged, ready-touse, in Hypo-vials. Pierce Chemical Co. 815-968-0747 438 Chemical identification kit, briefcase size, contains 1000 organic chemicals. Quantities of 1 ml or 1 gram are arranged by functional groups. Kit can serve as source of reference materials. $495; any one of five 200-unit sections is $99.50. Chem Service, Inc., West Chester, Pa. 439 Silar-5CP is a new high-temperature and high-polarity gas-chromatography phase. It will withstand temperatures up to 250°C for prolonged periods and can be exposed to 270°C for brief periods. Prom ising applications of this material are in the separation of mixtures of saturated, unsaturated, and polyunsaturated fatty acid methyl esters in the range,C20 and above. $35/10 grams. Applied Science Laboratories. 814-238-2406 440 Gas calibration standards, Mini-Cal, are certified to contain ± 2 % of the stated concentration of the gas. Each aerosoltype container holds 4 liters and is sup plied with two applicator tubes, one with a needle tip and one capable of accept ing a gas syringe needle. Nineteen gases are supplied in concentrations of 1000 ppm in helium. $12 each. Applied Sciience Laboratories. 814-238-2406 441 DNA-grade hydroxylapatite for the sep aration of nucleic acid components, called Bio-Gel HTP, is specially processed and then sized into an extremely narrow particle-size range. The material also shows a higher selectivity for doublestranded DNA over single-stranded DNA. It is a stable dry powder and costs $28/ 100 grams and $125/500 grams. Bio-Rad Laboratories. 415-234-4130 442 Mercury standard in gelatin simulates mercury-containing biological samples for interlab comparisons in mercury deter mination and for checking instrument, operator, and processing variabilities. The material is supplied as mercury stan dard in gelatin, 0.03 ppm, No. 11624, and mercury standard in gelatin, 0.1 ppm, No. 11626. Eastman Kodak Co. 716-724-4642 443
Potassium C h l o r i d e is a superior IR replacement w i n d o w . W h y ? Because it p r o v i d e s : • Better Transmission • Longer Life • Lower Solubility • Ease in Polishing • L o w e r Index and t h e price is the same as salt ( N a C I ) . W e also sell NaCI as w e l l as A L L replacement w i n d o w s for every IR s p e c t r o p h o t o m e t e r available. W r i t e us for more i n f o r m a t i o n — or call 2 1 6 / 2 4 8 / 7 4 0 0 .
HARSHAW
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The Harshaw Chemical Company Division of Kewanee Oil Company Crystal & Electronic Products Dept. 6 8 0 1 Cochran Road, S o l o n , Ohio 4 4 1 3 9 CIRCLE 9 4 O N READER SERVICE CARD
ANALYTICAL CHEMISTRY, VOL. 44, NO. 12, OCTOBER 1972
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