SUPERSPEED ANGLE CENTRIFUGE 15,500-rpm
31,000 χ G
REPORT FOR ANALYSTS
400-ml and ion exchange) accounted for a b o u t three o u t of five separations. T h i s represents a doubling over t h e corresponding 1946 figures, although t h e t a b u lations for t h e two years are n o t entirely comparable.
For all Your LaboratoryCentrifuging Requirements in both Science and Industry
T a b l e V.
SERVALL®
T y p e of P r e l i m i n a r y S e p a ration
Type
Internationally Known As "The Workhorse Of The Modern Research Laboratory."
A truly portable instrument, with separate transformer for remote con trol, easily operated in cold rooms, incubators, or practically any desired location and under any research conditions. CAPACITY:
Eight 50 ml stainless steel tubes or a wide range of other tubes in a variety of sizes and materials: 1, 5, 10, 15, 45 and 50 ml cellu lose nitrate; 1, 3, 10, 12, and 45 ml heavy pyrex; 32 ml autoclavable nylon; 6.5, 12, 50 ml autoclavable polyethylene.
This instrument, with its rugged, self-balancing direct drive, developed and introduced by "Servall" more than ten years ago, and which still maintains its reputation for being the finest available, is designed and engineered for all-day, vari able duty, and many years of trouble-free service. W R I T E FOR B U L L E T I N AC-121S. Designers, Manufacturers and Distributors of Laboratory Instruments Since 1930.
1\ΟΈΜ
'Servall"
SowwréÈlI9Inc·
Specialized
NORWALK CONN.
For further information, circle number 14 A-1 on Readers' Service Card, page 63 A
Qnom 0 «Λ ÔpeAatUwuL
JSff* FINE ORGANICS . I N O R G A N I C REAGENTS INDICATORS
Will/// OVER 4000 ITEMS / FROM A/ SINGLE SOURCE
MATHES0N, COLEMAN & BELL REAGENT CHEMICALS INCLUDE PRACTICALLY ALL THE ITEMS USED IN LABORATORY WORK! Our Reagent Organic Chemical conform not only to the specifications shown in our price list but also to the best literature values. The Reasent Inorsanic Chemical carry maximum-!imits-of-impurities labels. In addition to Reagent Organic and Inorganic Chemicals, many items of U.S.P., N.F., Practical and Techical grades are available. OUR NEW C A T A L O G LISTING M O R E T H A N 4000 ITEMS WILL BE SENT O N REQUEST
MATHESON
C O L E M A N & BELL
DIVISION OF THE MATHESON COMPANY. INC.
Manufacturing
Chemists
EAST RUTHERFORD. NEW JERSEY · NORWOOD CINCINNATI . OHIO
Adsorption Chromatographic Ion exchange Extraction Precipitation Distillation Dialysis Other 6
% of Total 19466 1955* 57.0
28.6
17.9 16.9 5.2 3.0
18.4 18.0 10.3 0.9 23.9
45 3 11 7
" Based on 402 entries. ' Includes several topics which were not separation methods, so direct comparisons are not very exact.
Summary About one in 14 papers currently being abstracted in Chemical Abstracts falls within the subject m a t t e r of analytical chemistry; in 1946 the figure was one in 26. T h e United States is leading, as it was in 1946, with respect to t h e a m o u n t of work done in this field. T h e increase in some other countries since 1946, however, has been substantial, so t h a t t h e U. S. now accounts for 2 3 . 8 % compared to 4 1 . 6 % in 1946. I n 1955, t h e leaders, following the U . S., were J a p a n , Germany, Russia, and Great Britain. I n 1946 the leaders were, after t h e U . S., G r e a t Britain, Russia, France, and Sweden. T h e most widely used languages were English, German, Russian, a n d French; in 1946 the order was English, Russian, French, a n d Spanish. T h e ratio of organic to inorganic is approximately equal now, compared to 5 8 % of organic versus 4 2 % inorganic in 1946. T h e analytical method most used both in 1955 a n d 1946 was t i t r i m e t r y (visual and instrumental), with colorimetry (visual and photoelectric), second. A close third place in 1955 was held by t h e various forms of spectrophotometry. In fourth and fifth places in 1955 were gravimetric methods a n d polarography. I n 1946, gravimetric methods held third place. Spectrophotometry and emission spectroscopy held fourth a n d fifth place a decade ago. Among t h e types of preliminary separation, t h e leader in 1955 a n d 1946 was adsorption. T h e 1955 figure (57%) was, however, greater t h a n t h a t in 1946. Second and t h i r d places in b o t h years were t h e same—namely, extraction a n d precipitation.
For further information, circle number 14 A-2 on Readers' Service Card, page 63 A
14 A
ANALYTICAL
CHEMISTRY
