THIS PEAK REPRESENTS 18.29% 1, 3-BUTADIENE

Chemist A took 14 min­utes to compute 17.58% 1, 3-Butadiene by cut and weigh techniques

Chemist Β took 7.5 min­utes to compute 18.25% by triangulation Chemist C took 7 min­utes to compute 18.19% by using a planimeter

Chemist D took 3 min­utes to compute 18.28% with a DISC Integrator

Chemist Ε took 1 minute to compute 18.28% with a DISC Integrator equipped with a Disc Automatic Printer

Now if you'd like to see how Messrs. D and Ε became so fast and so accurate — send for "Why Disc? ", a new publication comparing all peak area integration methods

Disc Instruments, Inc. 2701 S. Hatiaday St., saitta Ana, Calif. $2705 Phone: (714) 549-0343 · TWX 714-546-0434

Disc Instruments, Ltd. Ebberns Road, tfemel Hempstead Hertfordshire, England · phone: 57261-2

Disc Instruments GmbH 8000 MéRchen 50, Oacriauerstr. 5Π Germany · Tel: 54 22 91

M A N U F A C T U R E R S ' L I T E R A T U R E

Magnetic Susceptibility Systems. Complete magnetic susceptibility sys­tems for Gouy and Faraday measure­ments are presented in an eight-page brochure. Alpha Scientific, Inc., 460 Roland Way, Oakland, Cailf. 94621 601

Pyrolyzer. Bulletin PY-2, four pages, describes and illustrates Model PY-2 pyrolyzer and the four chambers avail­able for transmission condensate, ATR condensate, transmission vapor, and GC vapor methods of pyrolysis. Barnes Engineering Co., 30 Commerce Rd., Stamford, Conn. 06902 602

IR Spectrophotometer Supplies. Liq­uid-, gas-, and solid-sampling supplies, variable temperature and ATR ac­cessories, and beam condensers with related equipment are among the items included in Bulletin 83-A, 32 pages. Beckman Instruments, Inc., 2500 Har­bor Blvd., Fullerton, Calif. 92634 603

Solution Conductivity Handbook. Bul­letin 4090, 26 pages, describes principles of measurement, types of equipment, in­stallation of a conductivity system, and typical applications. Charts, graphs, and diagrams are included. Beckman Instruments, Inc., 2500 Harbor Blvd., Fullerton, Calif. 92634 604

Disc Electrophoresis. The technique itself is discussed and new apparatus is presented in an eight-page booklet. Canal Industrial Corp., 5635 Fisher Lane, Rockville, Md. 20852 605

Spectrophotometer. Bulletin No. 606 presents Model AA-120 atomic absorp­tion spectrophotometer. Cary Instru­ments, 2724 S. Peck Rd., Monrovia, Calif. 91016 606

Magnetic Flowmeters. Technical Bul­letin DS-7700 presents the Series 7700 solid state magnetic flowmeters with in­tegral signal converters. Brooks In­strument Division, Emerson Electric Co., Hatfield, Pa, 19440 607

Power Supplies. Regulated power sup­plies, amplifiers, modules, and program­ming devices are included in this 67-page, 1969-1970 catalog. Kepco, Inc., 131-38 Sanford Ave., Flushing, Ν. Υ. 11352 608

Circle No. 100 on Readers' Service Card

96 A • ANALYTICAL CHEMISTRY

D I S C

Side Inlet Model 3103

WELCH Turbo-Molecular Vacuum Pumps Welch Turbo-Molecular Pumps are clean, hydrocarbon-free, purely mechanical pumps for attaining high and ultra-high vacuum. They are cap­able of rapidly attaining extremely clean vacuum in the 10-6 to 10-7

decades. Turbos Are Non-Contaminating . . . Self Cleaning . . . use no pumping fluid and do not permit back-stream­ing during operation. They do remove hydrocarbons from the system in un­limited quantities without use of cold traps. Turbos Pump Noble Gases with ex­ceptionally high efficiency. Turbos Pump All Gases Without Se­lectivity . . . air, acetylene, helium, argon, benzine and all other gases at any point within operating range. Turbos Are Reliable—If the rotor is spinning, the turbo is pumping. It will not become "saturated" or "over­loaded." It does not "bury" gases, so cannot re-eject them into the system.

Call 312/677-0600 for full information on how a superior Turbo-Molecular Pump will fit your application better.

-2x10-' Blank-Off Pressue: 1-torr or lower Speed (Air): 260 liters/sec. over range of lxlO-2 to 1 χ 10-β torr.

Applications: Mass Spectrometry Particle Acceleration Electron Microscopy Sputtering Thin Film Metalizing Solid State and Surface Studies Purification of Metals Separation of Gases Ion Gauge Calibration Tube Evacuation Target Chamber Evacuation Space Chamber Evacuation

Turbos Offer Easy Leak Detection — They pump hel ium f rom 10-2 to 10-9

torr. No false signals by re-ejecting helium.

Turbos Simplify Roughing Problems. as roughing is done directly through the turbo-molecular pump . . . elimi­nates the need for roughing lines and valves. The turbo can be effectively started at 10 torr to take over the pumping action long before the fore pump's effectiveness drops . . . "no dead regions" in the transition from viscous to molecular flow . . . no mi­gration of fore pump fluid vapors into the system.

Turbos Are Safe—They neither use nor produce extremely high voltages.

Turbos Offer No Operational Prob­lems—They are not damaged by, and will recover rapidly from exposure to high pressure . . . have no hot fluids to be thermally cracked, with resul­tant downtime.

WELCH VACUUM PUMPS

SARGENT-WELCH SCIENTIFIC COMPANY 7300 N. UNDER AVENUE · SKOKIE, ILLINOIS 60076

Circle No. 47 on Readers' Service Card

Manufacturers' Literature

Digital Systems for Scientific Instru­ments. A short form catalog describes a number of digital systems used for data acquisition and/or control of sci­entific analytical instruments. Datex, Division of Conrac Corp., 1600 S. Mountain Ave., Duarte, Calif. 91010

609

Water Analysis. Bulletin No. 6 lists analyzers, monitors, and controllers for 52 different water, processing, and pol­lution tests from acidity to zinc. Delta Scientific Corp., Lindenhurst, L. I., N.Y. 11757 610

Gel Electrophoresis. Technical Bulle­tin 129 covers the development and physical considerations of electrophore­sis, the linear theory, and polyacryl-amide gel electrophoresis. E-C Ap­paratus Corp., 755 St. Marks St., Phil­adelphia, Pa. 19104 611

Tri-Stimulus Spectroradiometer. This instrument which measures the color composition, intensity, and spectral dis­tribution of any visible emissive or re­flective light is discussed in Bulletin 51, eight pages. Fisher Scientific Co., 711 Fisher Bldg., Pittsburgh, Pa. 15219 612

Laboratory Equipment and Accessor­ies. Equipment and accessories for chemical, biological, and clinical lab­oratories are described and illustrated in Catalog 1969, 128 pages. Gelman In­strument Co., P. O. Box 1448, Ann Ar­bor, Mich. 48106 613

Labeled Compounds. Labeled com­pounds and research biochemicals are listed in Catalog No. 4, 102 pages. In­ternational Chemical & Nuclear Corp., Chemical and Radioisotope Division, 2727 Campus Dr., Irvine, Calif. 92664

614

Digital Indicator. The H500 Series digital indicator, a solid-state instru­ment with flexibility to perform a va­riety of measuring jobs, is presented in a four-page illustrated brochure. How­ell Instruments, Inc., 3479 W. Vickerv Blvd., Fort Worth, Tex. 76107 615

Glass and Plastic Laboratory Ware. PL-69 is a price list supplement to Cat­alog K-68. Both reusable and dispos­able glassware and plastic ware is in­cluded in the 64-page supplement. Kimble, Owens-Illinois, Inc., Toledo, Ohio 43601 616

98 A • ANALYTICAL CHEMISTRY Circle No. 111 on Readers' Service Card

HARLECO présents a now lead di­oxide exposure system utilizing the Huey Sulfation plate. This method surpasses the traditional lead can­dle, used to measure sulfur dioxide air pollution, in both economy and accuracy. To expose the HARLECO sulfation plate simply remove the petri dish lid and place it in a HARLECO hold­er, securing the plate in an upside down position. The potri dish thus serves a two-fold purpose . . . as shelter and as a shipping container. (Reagents for tutbidimetric anal/sis of sulfation plates, according to the Huey method, are available from HARLECO.) Completely self-contained in a plas­tic petri dish, the HARLECO sulfa­tion plate eliminates the difficulties encountered in the tedious prepara­tion of the sulfation candle, as well as the expense of a shelter for the housing of the sampler.

For further information concerning this item and other items in the air and water pollution control field, write to HARLECO. Hucy Sulfation Plates HARLECO Item No. 64339

Pkq. - 25 — S40.00 Pkg. - 100 — 150.00

Huey Sulfation Plate Holder HARLECO Item No. 64361

1 - 24 units — S2.75 each 25 - 49 units — 2.00 each 50-99 un i ts— 1.75 each

100 plus units— 1.65 each

Circle No. 69 on Readers' Service Card

100 A • ANALYTICAL CHEMISTRY

Manufacturers' Literature

Isolation Filters. High performance isolation filters designed for any elec­tro-optical detection or sensing system operating in the TJV-VIS-IR frequency ranges are described in a four-page bro­chure. Laser Optics, Inc., P. O. Box 3, Danbury, Conn. 06810 617

Frequency Calibrator. Model S1315A, a solid-state instrument for checking raw crystals and other fundamental fre­quency devices, is described in a four-page brochure. Motorola Communica­tions and Electronics, Inc., 1301 E. Al­gonquin Ed., Schaumburg, 111. 60172

618

Agarose Gel. Sepharose 6B, a bead-gelled agarose of approximately 6% con­centration, is discussed in a new bulle­tin. Pharmacia Fine Chemicals, Inc., 800 Centennial Ave., Piscataway, N. J. 08854 619

Calculator. Specifications for Model 700, a third-generation programmable calculator, are offered in an eight-page brochure. Typical programs are also listed. Wang Laboratories, Inc., 836 North St., Tewksbury, Mass. 01876

620

Calculators. Features and functions of the 300 Series calculators along with problems and keyboard solutions arc presented in a compact 16-page book­let. Wang Laboratories, Inc., 836 North St., Tewksbury, Mass. 01876

621

SpectraSpan Atomic Analysis Sys­tems. A new eight-page brochure de­tails theory of operation, character­istics, and operations of Model 101 re­search system and Model 201 multi­element system. Spectrametrics, Inc., Second Ave., Northwest Park, Burling­ton, Mass. 01803 622

Precision Thermistors. Character­istics of precision thermistors and linear output thermistor components are de­tailed in an eight-page catalog. Yellow Springs Instrument Co., Inc., P. O. Box 279, Yellow Springs, Ohio 45387 623

Surfactant Screening Tests. One of the tests included in this six-page book­let is the determination of the contact angle of surfactant solutions on various substrates. Rohm and Haas Co., In­dependence Mall West, Philadelphia, Pa. 19105 624

maybe your monkey is sick!

Check his temperature with a YSI Tele-Thermometer and thermistor probe. In just a few seconds you'll know if he has a fever.

Or perhaps you're inter­ested in heart chamber, intra­muscular, and major vessel measurements. Maybe you are conducting thermal dilution studies, or want to implant a temperature sensing device in biological tissue.

When you need to measure temperature — lab animals to frozen food packages, beneath the soil, under the sea, or in the air — there is a YSI probe and Tele-Thermometer to do the job. Or if you want to con­trol t empera ture , we have equipment for that, too.

Take care of your monkey, and write for our catalog of thermistor based temperature measurement and control equipment.

Circle No. 71 on Readers' Service Card

Circle No. 74 on Readers' Service Card

ι „ air pollution

Harleco® 60th & Woodland Avenue

Philadelphia, Pennsylvania 19143 YELLOW SPRINGS INSTRUMENT CO.

YELLOW SPRINGS, O H I O 4 5 3 8 7

EXCLUSIVE f, ̂ΉΠ-.ζΑ.Έ*Π?

N E W SAFETY SPURT CAP* Saves clothes

Prevents burns and injuries

Sudden spurts of b o i l i n g c h e m i c a l shooting out of a test tube will be rendered harmless by striking t h e S p u r t C a p mounted by a clip on any t e s t t u b e and shielding the open end of the tube with­out sealing it.

Cap b reaks up stream through inter­nal baffle design.

^Canadian Patent Pending

N E W DRYING TUBES with

STANDARD TAPER FITTINGS

Fittings are molded polyethylene with inner (male) standard taper joints with protruding end. Internal cross bars restrict passage of solid materials (may be cut out if not needed). Also useful in connecting standard taper apparatus. Available in 4 ", 6 "and 8 " lengths for 14/20 * and 24 /40 f .

See your nearest laboratory supply dealer.

Send for NEW 80 page catalog 469 For your FREE copy write Dept. A-7

BEL-ART PRODUCTS PEQUANNOCK, N. J. 0 7 4 4 0

The MOST COMPLETE l ine of Plastic L a b o r a t o r y W a r e a v a i l a b l e f r o m ONE source

Circle No. 90 on Readers' Service Card

Manufacturers' Literature

Electron Microscope. A 20-page bro­chure traces the development history of the electron microscope. Picker Nu­clear, 1275 Mamaroneck Ave., White Plains, N .Y . 10605 625

Graphite Materials and Products. An eight-page brochure describes graphite materials and products and lists prop­erties and characteristics of a series of high-purity grades of graphite. Ultra Carbon Corp., 1310 N. Madison St., Bay City, Mich. 48706 626

Research Enzymes and Biochemicals. More than 230 high-purity enzymes and related biochemicals for life science re­searchers are listed in a 28-page cata­log. Information such as enzyme source, activity, purity, assay, and packaging is included. Worthington Biochemical Corp., Freehold, N. J. 07728 627

Ovens and Incubators. Forced circu­lation and gravity ovens, vacuum ovens, and incubators are among the items included in Bulletin No. 320, 16 pages. Precision Scientific, 3737 W. Cortland St., Chicago, 111. 60647 628

Determination of Serotonin and Nor­epinephrine. A six-page booklet pre­sents a total system for the fluorescence assay of serotonin and norepinephrine. Regis Chemical Co., 1101 N. Franklin St., Chicago, 111. 60610 629

Spectrochemical Supplies. Pure ma­terials, qualitative, semiquantitative, and quantitative standards, and pre-weighed diluents, buffers, and fluxing materials are included in a 25-page cat­alog. Spex Industries, Inc., Box 798, Metiichen, N. J. 08840 630

Mass Flowmeters. Bulletin 506A ex­plains the features and operation of the company's line of nonlinear mass flow­meters. Technologv/Versatronics, Inc., 506 S. High St., Yellow Springs, Ohio 45387 631

Spectrophotometers. Models 111 and 116 second generation GC-IR spectro­photometers are presented in Data Sheet No. 29, six pages. Wilks Scien­tific Corp., South Norwalk, Conn. 06856 632

NEW ÊWILm WW

from NORTHERN SCIENTIFIC

• 5" CRT Display • 10 Milli­volt Input Sensitivity • Built-in Area Integration • Optional Search Ramp • Pre- and Post-Delay Selections • Teletype Readin/Readout Option

512 CHANNELS

$ . ;4950 1024 CHANNELS $5,450 2048 CHANNELS $6,150

F.O.B. MIDDLETON, WISCONSIN

The NS-560 (SAC Series) Signal Averaging Computer provides the experimenter or technician with the most versatility, accuracy and efficiency at the lowest possible cost. It is a totaling type aver­ager with a fixed program to pro­vide a "non-rising" baseline. The unit has several optional features which extend its use in many medical applications as well as nuclear magnetic resonant meas­urements.

If you have an experiment which has noise as a problem, or just di­gitizing analog signals, the NS-560 may solve your problem.

For full details, write today.

S C I E N T I F I C / I N C . kliUhiiil P.O. Box 66, Middleton, Wisconsin 53562 Phone 608/836-6511 TWX 910-280-2521

Circle No. 98 on Readers' Service Card

VOL. 4 1 , NO. 8, JULY 1969 • 103 A

NS-5BO SIGNAL AVERAGING

COMPUTER

N O R T H E R N

Record weight changes at pressures

as low as 10 10 TORR

Sensitivities down to 1/10th MICROGRAM Loads up to 100 GRAMS Precision up to ONE PART/10 MILLION of sample

RECORDING ELECTROBALANCES THOUSANDS NOW IN USE

• OUTGASSING STUDIES • SPACE SIMULATION • THRUST MEASUREMENT • ADSORPTION ISOTHERMS • REACTION RATES • THIN FILM MONITORING

Phone or Write for details

Circle No. 113 on Reader's Service Card

Manufacturers' Literature

Company Periodicals

Requests for copies of the following publications, catalogs, etc., should be sent directly to the address shown. Business or professional letterheads are requested.

Disc Electrophoresis Newsletter, No. 11, April 1969. Several types of sepa­rations, recent clinical developments, and new equipment and accessories are presented. Canal Industrial Corp., 5635 Fisher Lane, Rockville, Md. 20852

Modern Precision, Vol. 29, No. 1. This issue includes an article discussing the use of IR analyzers to monitor CO in automobile tunnels. Leeds and Nor-thrup, Sumneytown Pike, North Wales, Pa. 19454

Infrared News, No. 1, April 1969. Model H1200 Infragraph, an infrared double-beam spectrophotometer, is de­scribed and illustrated in this issue. Wilks Scientific Corp., South Norwalk, Conn. 06856

Information, No. 68. Flame photo­metric methods of analysis and elec­tronic data processing in connection with optical analytical instruments are among the topics discussed. Carl Zeiss, Inc., 444 Fifth Ave., New York, Ν. Υ. 10018

Information, No. 69. A discussion of the IPM 2 integrating photometer, an instrument for exacting weight determi­nations of objects at or below the re­solving power of light microscopy, is presented in this issue. Carl Zeiss, Inc., 444 Fifth Ave., New York, Ν. Υ. 10018

Chromatography Lipids, Vol. 3, No. 2. Additional information is given on PPE-20, a polyphenyl ether stationary phase, and a number of new products are listed. Supelco, Inc., P.O. Box 628, Beliefonte, Pa, 16823

MPI Applications Notes, Vol. 4, No. 3. Double-beam photometry is discussed in this issue. Principles, instrumenta­tion, sources of error, and the use of the logarithm of absorbance for quali­tative analysis are covered. McKee-Pedersen Instruments, P. O. Box 322, Danville, Calif. 94526

Current Laboratory Practice, Vol. 1, No. 3. A screening method for gamma globulinopathies using Sepraphore III cellulose polyacetate support medium is presented. Gelman Instrument Co., 600 S. Wagner Rd., Ann Arbor, Mich. 48106

JUST HATCHED

AT BIO-RAD OUR NEW CATALOG

Price List "U"

This 56 page c o m p e n d i u m of chromatographic information fea­tures new applications sections on B i o - R a d ma te r i a l s for ion ex­change, gel filtration, and adsorp­tion. In addition, you will find im­portant and hard-to-find data on the latest work in the chromatog­raphy of proteins, including ma­terials and systems for the synthe­sis and degradation of peptides. To get your free copy of "U" , please fill out the coupon.

Gentlemen: please send me Price List "U". Dept. A-5

Name

Organization

Street City

State

BIO-RAD 32nd and Griffin Avenue Richmond, California 94804

Circle No. 108 on Readers' Service Card

VOL. 4 1 , NO. 8, JULY 1969 • 105 A

CAHN D I V I S I O N

VENTRON I N S T R U M E N T S C O R P .

7500 Jefferson St.. Paramount, Calif. 90723

(213) 634 1935

27 Essex Rd., Dartford, Kent, U.K.. Ph. 21540

Zip

Laboratories