Micro DTA & DSC i n 1 instrument? EDITORS' C O L U M N Τ η T H E ARTICLE " A n a l y t i c a l C h e m i s t r y in Y u g o s l a v i a , " [ANAL. C H E M . , 41 ( 8 ) , 24 A (1969) ] , it w a s
s t a t e d t h a t t h e University of Bel g r a d e is t h e oldest u n i v e r s i t y ( a b o u t 100 y e a r s ) in t h e c o u n t r y . Several letters from Yugoslavia have pointed o u t t h a t while t h e Univer sity of Belgrade celebrated its cen t e n n i a l a few weeks ago, t h e tercen t e n n i a l celebration of t h e U n i v e r s i t y of Zagreb is being held in 1969. T h e U n i v e r s i t y of Zagreb h a s existed b y t h a t n a m e only since 1874, b u t its origins c a n b e t r a c e d t o 1662 when Jesuits founded a col legiate institute of philosophy in t h a t city. T h e tercentennial cele b r a t i o n m a r k s t h e elevation of t h a t i n s t i t u t e b y K a i s e r Leopold I of A u s t r i a - H u n g a r y in 1669 t o t h e r a n k of a faculty of philosophy. T h e m o d e r n definition of a u n i versity requires t h e existence of four faculties, a n d confusion often arises as t o whether t h e founding d a t e refers t o t h e origin of t h e a n t e cedent institution or of t h e fullfledged university. As for t h e early history of chem i s t r y in C r o a t i a , S. Miholic, in Bul letin Scientifique, 3 (2), 33, states, " O n e can almost s a y t h a t t h e a l chemistic period in c h e m i s t r y lasted in C r o a t i a till t h e middle of t h e 19th century. T h e only other ex p e r i m e n t a l w o r k in chemistry w a s t h e n u m b e r of analyses of C r o a t i a mineral waters made by apothecar ies, of which some a r e r e m a r k a b l y well done. T h e opening of t h e first technological middle school in Z a greb in 1854 m a r k e d t h e beginning of a n e w era. I n 1856 t h e first course of experimental chemistry was delivered a t t h a t school b y C a n o n J . T o r b a r (1824-1900·) p h y s icist a n d later president of t h e Y u g o s l a v A c a d e m y of Sciences. F r o m 1859 t h e course i n . c h e m i s t r y was given b y P . Zulic, w h o wrote t h e first t e x t b o o k of c h e m i s t r y (1866). A further step w a s m a d e when t h e U n i v e r s i t y of Zagreb w a s
Detection of an Extremely Small Peak (C). Probe: GS(25 /Λ) Sample: Tri-caleinm silicate— 37 mg. Sensitivity: 20 μν full scale Reversible crystalline transitions in the 900 to 1,000°C range. Tiny peak (C) distant only 10° C from peak (B) is perfectly detected. ΔΤ signal for peak (C) does not exceed 0.02°C.
PrécisetnentS The fourth generation micro thermal analyzer developed by Professor Mazieres of the University of Paris is now available in the U . S . through the Infotronics sales and service organization. The M.-4 D T A measures temperature differentials in the —160°Cto + 1600°C range with 0.1°C resolution. Temperature is programmed by a front panel switch at rates of 1°C to 20°C/min. Full atmospheric control is maintained with inert gas in the sample cavity. But that's only part of the story. The M-4 also fund ions effectively as a differential scanning calorimeter—wit] H»I 11 the use of special cells. Quantitative measurement?· >.. η be obtained with excellent accuracy and with little calibration.
τ
Key to the M-4's sensitive performance for D T A and D S C lies in its patented probe design which features three hollow thermo couples. Extremely high efficiency of detector operation is the result of close contact with small sample sizes— 0.6 μΐ tO 25 μ\. Applications include all phases of organic and inorganic chemistry, such as polymers, elastomers, crystallography, ceramics, metallurgy, and quality control of feeds, foods and pharmaceuticals. To learn more, write for Data File DTA-4.
INFOTRONICS CORP.
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ANALYTICAL CHEMISTRY, VOL. 4 1 , NO, 14, DECEMBER 1 9 6 9
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established in 1874. The first professor of chemistry A. Velkov appointed in 1875, and a laboratory of chemistry opened in 1876."
MOLECULAR MOVEMENT STUDIED BY LASER
Two scientists from the Akron University's Institute of Polymer Science have reported at the national meeting of the Society of Rheology (St. Paul, Minn., Oct. 1922) the development of a laser device for measuring molecular movement. Coherent red light from a sixfoot laser tube is passed through a solution of polymer macromolecules, whereupon a Doppler shift occurs that is detected by a photoelectric cell. Circuitry developed by the researchers, Dr. J. E. Frederick and Thomas F. Reed, filters noise and separates and records various frequencies and their harmonies. The laser tube for the apparatus is mounted on a one-ton concrete slab supported by steel " I " beams, and the entire system of laser tube, glass vessel for sample, and photocell are supported on heavy springs to absorb vibrations above 10 Hz. We are encouraged to remark that although the implementation •of laser devices in 'analytical and associated instrumentation has been slow, there are a t least encouraging signs that progress is being made, however deliberate the pace continues.
No sacrifice in response or efficiency. Choose a Sargent combination pH electrode by size alone.
Both of these Sargent combination pH electrodes cover the entire pH range from 0 to 14 pH. Both offer fast, linear r e s p o n s e even in highly acid solutions. Response to alkali ions is insignificant below pH 12.5 (at higher pH, response is low and stable). Both electrodes achieve high efficiency, with a millivcIt/pH response close to the Nernst coefficient. And you get this kind of performance over a range of 0 to 80°C. These electrodes also feature all-glass, shock-resistant construction. No rubber or plastic to contaminate samples. No pockets to trap solutions or hamper cleaning. Stainless-steel caps provide sure, strong clamping. What's the différence, then, between these two combination pH electrodes? Size alone. For samples as small as Vz ml or those in extremely confined volumes, choose the miniature electrode (priced at $42.00). Otherwise, your best choice is the standardsize ($40.00). Both come with connecting cable and plugs to fit all popular pH meters. Call your Sargent man or write to us for a closer look at these combination pH electrodes or for data on our complete line of glass and reference electrodes.
NEW MASS SPECTROMETER
A new mass spectrometer which weighs less than 2 oz, using three mesh electrodes has been developed by General Electric. Ions in gases are sorted according to their masses in the three-dimensional quadrupole electric field inside the electrodes, and a electron multiplier device is used to measure the number of trapped ions. Further information will appear in a later issue.
SARGENT-WELCH Scientific instruments, apparatus, chemicals. Sargent-Welch Scientific Company 7300 N. Under Ave.; Skokie, Illinois 60076 Chicago/Anaheim/Birmingham/Cincinnati Cleveland/Dallas/Denver/Detroit Springfield, N.J./Toronto/Montreal/Vancouver
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ANALYTICAL CHEMISTRY, VOL. 4 1 , NO. 14, DECEMBER 1969
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