NEWS performance on finer particles of 70to 80-mesh. The authors explained this result by pointing out that the support was chemically similar to the liquid phase in these experiments and cannot be regarded as inert. A method for the determination of separation factors from unresolved twocomponent peaks was developed by Sideman and Giladi. A study of nitro gen isotope enrichment was used as an application of this method. A separa tion factor of 1.0011 for a 28/29 nitro gen isotope mass ratio obtained experi mentally was in good agreement with the value 1.0007 calculated from vapor pressure measurements. A detailed description of a GC ap paratus useful for the qualitative and quantitative analysis of microgram amounts of flavor volatiles from edible fats was given by Swoboda. Individ ual peaks were identified with the aid of Kovats' retention index method and the determination of the carbon skele ton by catalytic reduction of the com ponent to its corresponding hydrocar bon followed by GC identification of the product formed. Schomburg reviewed the chemistry of boron alkyls and hydrides and demonstrated the value of GC for de termining equilibrium concentrations of products formed in the transalkylation of boron alkyls, boracyclanes, and bisborolanes. Grant and Vaughan prepared trimethyl silyl ethers of phenols with hexamethyldisilazane for the separa tion of complex phenolic mixtures. Glass capillary columns coated with silicone oil MS 550 [Midland Silicones Ltd.] gave well defined symmetrical bands for silylated phenols, cresols, and xylenols boiling in the range 190300° C. The analysis of millimicroliter quan tities of the permanent gases hydrogen, oxygen, nitrogen, argon, methane, car bon monoxide, carbon dioxide, krypton, xenon, and neon was described by Berry. An ionization detector with high purity helium used as carrier gas was employed [metastable (23S) he lium atoms, 19.8 eV energy]. The limit of detection ranged from 5 X 10~8 to 5 Χ 10 -7 cc. of the permanent gases. A method for adequately purifying the helium carrier gas and the variation of detector signal with flow rate, gas pres sure, and detector temperature were discussed in detail. Trace analysis of hydrocarbons (up to C e ) was performed by Huyten, Rijnders and van Beersum on alumina columns containing ca. 2% water. Ap paratus was described which is useful for direct quantitative analysis in con centrations down to ca. 0.003 p.p.m.
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Circle No. 51 on Readers' Service Card
VOL. 34, NO. 10, SEPTEMBER 1962 · 81
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