REPORT
FOR
ANALYTICAL
CHEMISTS
Anal. Chem. 1960.32:17A-29A. Downloaded from pubs.acs.org by UNIV OF TEXAS SW MEDICAL CTR on 10/13/18. For personal use only.
Atomic Absorption Spectroscopy J. W. Robinson,
Esso Research
Laboratories, Baton Rouge, Louisiana
Introduction The determination of trace metal impurities has always provided a challenge to the analytical chemist. With progress in industrial technology and in all the disciplines of science, this problem becomes increasingly important. Considerable technical effort has been spent on improving well known instrumental techniques—spectrography, polar-
ography, ionophoresis—and improving chemical methods, e.g., by solvent extraction, organic reagents.
As most of these processes
already well known, a major breakthrough in this field of analytical work will probably come
are
about only by the development of Atomic absorpa new technique. tion spectroscopy seems to be such a technique. As far back as 1955, A. Walsh and his coworkers pointed out that the phenomenon responsible for Fraunhoffer lines could be utilized for trace metal analysis. His experiments showed that only comparatively simple equipment was required for the detection and determination of several metals at the parts per million level of concentration. Since that time, further pioneering work on his part has established this as a scientific field of major importance, potentially capable of solving composition
equilibrium and kinetic problems in branches of science. It seems possible that with the devel-
many
opment of commercial equipment for this work, its value will be fully realized.
Principle The analytical
application is the fact that metal atoms absorb strongly at discrete, characteristic wave lengths, which coincide with the emission spectra lines of the particular metal. A simple presentation of the process is shown in Figure 1 (page 19 A). The process for emitting spectra, as in flame photometry and emission spectrography, is the reverse based
on
VOL. 32, NO. a, JULY 1960
·
17 A
REPORT
the latest word in automatically'controlled, refrigerated centrifuges
• AUTOMATIC CONTROLS • SUPERSPEEDS · RCF UP TO 37,000 x G • CONTINUOUS FLOW • MODERN, FUNCTIONAL DESIGN
No fewer than five different rotors may be used in the new SERVALL RC-2: Superspeed, Large Capacity,
Multi-Tube Superspeed, Horizontal, Virus & Particle Counting (with others under development). GyroAction Direct Drive: the only signifi-
cant self-centering development in a decade; provides smoother operation than any other drive system.
Continuous Flow System permits gallon quantities of material to be separated directly in tubes. Automatic Acceleration, Dynamic Braking, and exclusive Dual Automatic Temperature Control for accurately maintaining material temperature within ±1°C at all times. Basic unit includes standard 8 x 50 ml superBulletin AC-7RC-2. speed rotor. SERVALL CENTRIFUGES SERVE YOU BEST
/i
