REPORT FOR
ANALYSTS
startling, improvement in sensitivity. Used together, however, their power and effects compounded, they represent real progress in determining trace elements. A trace element may soon be regarded as one in the parts per billion range or below rather than parts per 100,000. Figure 3 . C o m p a r i s o n o f h o l l o w c a t h o d e d i s c h a r g e a n d d.c. arc d i s c h a r g e o f the lithium lines a t 6 7 0 7 Α., using a JAco-Ebert s p e c t r o g r a p h in the 4 t h o r d e r a t 0 . 7 7 A . / m m . r e c i p r o c a l dis persion
Courtesy Esso Research & Engineering
Co.
THE IDEAL PRESS FOR MAKING KBR PELLETS FOR INFRARED
SPECTROSCOPIC ANALYSIS A l s o for Forming pellets for x - r a y a n d other types of spectroscopic analysis
the wanted element may be extracted with water. Extremely low blanks are claimed with this technique (see page 892). New photographic emulsions are also getting their share of attention. The same emulsions used to photograph a pretty young lady by the flickering light of her escort's cigarette lighter are beginning to aid the spectrographer in photographing the weak spectral lines produced by a few elusive atoms. Individually, techniques and instru mentation such as those discussed offer a significant, but perhaps not
Extension of Scope It is often stated that the spectrographic method is confined to the de termination of the metals. These, plus such determinable nonmetals as phosphorus and fluorine, number about 70 elements. The rare gases, carbon, oxygen, nitrogen, hydrogen, and the halogens remain aloof, unwilling to have their noses counted spectrographically. The hold-out elements are, however, gradually being brought into the fold. V. A. Fassel and associates at Iowa State College have recently developed a novel procedure for measuring the oxygen content of metals, a method which promises to outperform standard vacuum fusion techniques. The oxygen is released from the sample by using a d.c. arc in an enclosed chamber con taining a fixed pressure of argon. P-t. ANODE
•
Hydraulic 2 0 Ton C a p a c i t y Press in op• Accurate a l i g n m e n t eration • G u i d e d m o v i n g platen • Sturdy 3 c o l u m n construction • Even pressure d i s t r i b u t i o n f o r u n i f o r m l y dense pellets • Self-contained • Bench m o u n t e d • Hand o p e r a t e d • 9 " χ 9 " platen area • 2 2 " m a x . vertical o p e n i n g , adjustable
A multi-purpose unit with q u i c k l y a d j u s t e d vertical opening, by handwheel, per mits many different set-ups in minimum time. Used around the world for RESEARCH, C O N T R O L & TESTING. Available accessories include: Heat ing and Cooling Platens; Temp. Con trols, Auxiliary low pressure guages; Fast air closing; Extruding units; Testing units, etc.
ANODE
CHAMBER
ANOLYTE CATHODE
CHAMBER*
CATHOLYTE CATION PERMEABLE MEMBRANE Pt
CATHODE
Figure 4 . Electrodialysis cell with ion exchange membrane. Silico sample dis solved in NaOH is placed in polyethylene anode chamber and sodium ions are removed by electrodialysis through the membrane. The resulting silicate matrix is extracted with water to concentrate impurities which are then determined spectrographically SECONDARY SLITS MULTIPLIERPHOTOTUBES
-GRATING
PRIMARY SLIT
Available in 30 and 50 ton sires. Write for Bulletin.
LOOMIS E N G I N E E R I N G & MANUFACTURING CO. Dept. A , Route 4 6 , C a l d w e l l , N . J . Circle No. 13 A an Readers' Service Card, page 77 A 18 A
·
ANALYTICAL CHEMISTRY
Figure graph g e n , it almost
5. A p p l i e d Research Laboratories' Q u a n t o v a c , a direct r e a d i n g spectro f o r d e t e r m i n i n g c a r b o n , p h o s p h o r u s , a n d sulfur in s t e e l . Flushed w i t h n i t r o m a y b e used d o w n to 1 7 0 0 A. w h e r e air a n d w a t e r v a p o r a b s o r b r a d i a t i o n completely
