REPORT FOR ANALYTICAL CHEMISTS
ΥΛο you know t h a t the conventional batchtype rotor of the Servall SS-1 Superspeed Centrifuge* ruay be adapted for the unique Servall 8- to 1-Tube Continuous Flow System?
KN$*Sv'
You can centrifuge gallon quantities of material in one continuing operation at flow rates of up to 400 ml per minute. We have been delivering Servall Continuous Flow Systems for more than a year. This work-proven instrument is available now. Write us for infor mation and literature: Bulletin
AC-12-KSA
* For models with rotors, bear ing Serial Nos. 1800 and up. Continuous Flow System available with many other Servall Superspeed Centrifuges WÊÊ ·,-; I
An independent company: not connected with any other centrifuge manufacturer. Estab-
Ivan Sorvall, Inc. NORWALK CONNECTICUT
Circle No. 34 A on Readers' Service Card, page 97 A
34 A
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ANALYTICAL CHEMISTRY
Figure 5. Podbielniak "Thermocon" Series 8700, an automatic recording apparatus for low-temperature separation, plotting dual curves for boiling point, and thermal conductivity. (Courtesy of Podbielniak, Inc.)
cals, such as sulfate, or compounds, such as pyridine. Although efforts toward automation have centered on measurement of desired constituents, very significant progress has been made in various other unit operations. Only brief mention can be made of these. Sampling may be a very formidable problem in heterogeneous materials, especially solids. For example, how can one automatically sample the Rocky Mountains of Utah for potassium? There are automatic selectors for process streams, of course, as there are also automatic grinders and mixers. Relatively little automation has been achieved in measuring batch samples, whether solid, liquid, or gas. Also little has been done to eliminate the manual preliminary operations so often necessary prior to separation a n d / o r measurement. Fusion, dissolution, complexation, and adjustment of conditions, such as p H and oxidation state, are common examples. Unless the constituents of a polycomponent system can be measured in the presence of each other, there must be separation (s). Volatilization, precipitation, electrodeposition, and partition methods of several kinds involve well known operations. Very great difficulties may center here, as in a petroleum
Figure 6. "Kromo-Tog" Model K-5 separator and recorder for gas chromatography. (Courtesy of Burrell Corp.)
sample. This subject is extensive, but mention may be made of some automation. Three noteworthy examples are Podbielniak stills, mass spectrometers, and gas chromatographs (Figure 5). I n the last two, separation and measurement may not appear to the analyst as discrete operations. Analytically inexperienced teachers who disparage qualitative analysis should note t h a t in all three of these methods one has to determine what is being measured. Final note may be made of at least partially automated aids for handling analytical data, such as many kinds of calculators and I B M sorting machines. A complicated example is the automatic data processing equipment in use at the N a tional Bureau of Standards for emission spectrometric analyses. Simultaneous determinations of up to 18 elements are recorded on punched cards for high-speed statistical analysis for homogeneity. Conclusion
Much has been done in the past 50 years toward automating analytical methods. Because of their high cost, and often their limited application, some of the present instruments can hardly be afforded or justified in many small laboratories. Even if they could be, we still seem a long way from having the instrument which will determine all desired constituents, in any relative proportions, in any kind of inorganic or organic substance.
