GAS FACTS published periodically were observed to have activ for analytical chemists ity. In an anhydrous system
the reaction was found to be significantly affected by 0-5 ppmv oxygen. For example, such traces of oxygen accel erated the FeO-catalyzed For many years it's been conversion of CO from 1.80 suspected that low concentra to 13.09%/year. Interest tions (20 ppmv) of carbon ingly, an increase in oxygen monoxide reacted unpredict concentration in the FeO ably with steel cylinder sur system to 30 ppmv then faces. Measurements carried decreased the reaction rate out at Scott have shown to a loss of 2.97%/year. that the reaction proceeds It was hypothesized that at at room temperature. It was the higher concentration,
CO interaction with metal surfaces
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Loss of CO in untreated steel cylinders. Linear least squares fit.
found too that the rate varies significantly from cylinder to cylinder. Batches of 20 cylin ders showed concentration losses rangingfrom< 1 % to >5%/year. Mean con centration change was -1.07%/year. Good agreement was found between CO loss and COz formation. Eg, loss of CO of 0.188 ppmv/year was off set by C02 formation of 0.200 ppmv/year. The reac tion was determined to involve various metal oxides on the inner surface of the cylinders. All the iron oxides
Hydrophobic Selectivity in Micellar and Hydro-Organic Reversed-Phase Liquid Chromatography 876 Hydrophobic selectivity is used to demonstrate significant differences between the use of micelles and organic solvents as the mobile-phase modifiers for reversed-phase LC. The different behavior with micellar eluents is attributed to the nonhomogeneous nature of the micelles' microenvironment, which is similar to that of the alkyl-bonded stationary phase. Morteza G. Khaledi, Department of Chemistry, University of New Orleans, New Orleans, La. 70148 Anal. Chem., 60 (1988)
Determination of Polycyclic Aromatic Hydrocarbons in a Coal Tar Standard Reference Material 887 GC and LC are used to quantify 30 polycyclic aromatic hydrocarbons in Standard Reference Material 1597, "Com plex Mixture of Polycyclic Aromatic Hydrocarbons from Coal Tar." Stephen A. Wise*, Bruce A. Benner, Gary D. Byrd, Stephen N. Chesler, Richard E. Rebbert, and Michèle M. Schantz, Organic Analytical Research Division, Center for Analytical Chemistry, National Bureau of Standards, Gaithersburg, Md. 20899 Anal. Chem., 60 (1988)
Resolution of Electrostatic and Steric Factors in Aqueous Size Exclusion Chromatography 895
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oxygen competed for active sites on the metal oxide sur face, hindering adsorption of CO. When water was intro duced into the system, FeO activity was reduced so CO loss was only 0.09%/year. Scott has developed unique cylinder wall treat ments to reduce CO losses to
