tative composition. Table I1 indicates the impurities actually found and their concentration ranges. I n the right hand column are shown concentrations a t which components were actually dctected under the conditions of these esperiments. In many of these cases the response from less material could certainly have been differentiated from base line noise but no eff 01t was made to determine actual minimum detcctablc limits. The values represent rather the order of magnitude of the limits under the conditions used, and together with data of sample size nnd split ratio, they indicate the o d e r of magnitude of the mass of material which the appaiatus will detect. For many of the impurities which were well sepnrated a larger sample size could have been used, thus enabling the determination of even smaller quantities. CONCLUSIONS
In this type of essential analytical work both highly efficient columns and highly sensitive detectors are necessities. The invention of capillary chromatographic columns by Golay (6) provided the separating tool, and the triode cell
Table II. Concentration of Trace Components in Six Samples of Finished Styrene
Compound Benzene Toluene Ethylbenzene p-Xylene m-Xylene o-Xylene Styrene Cumene Unknown n-Propylbenzene m-Ethyltoluene p-Ethyltoluene a-Xethylstyrene Unknown tert-Butylbenzene Isobutylbenzene sec-Butylbenzene m-Viny ltoluene p-Vinyltoluene &Methylstyrene '
Range, P.P.M.
OMDL,@ P.P.M.
