GAS FACTS
BRIEFS Trace Level Determination of Titanium in Real Samples by Alternating Current Voltammetry 2402
published periodically were observed to have activfor analytical chemists ity. In an anhydrous system
the reaction was found to be significantly affected by 0-5 ppmv oxygen. For example, CO interaction with such traces of oxygen accelmetal surfaces erated the FeO-catalyzed For many years its been conversion of CO from 1.80 suspected that low concentra- to 13.09%/year. Interesttions (20 ppmv) of carbon ingly, an increase in oxygen monoxide reacted unpredict- concentration in the FeO ably with steel cylinder sursystem 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,
The proposed method permits the voltammetric determination of titanium (IV) in the presence of a large excess of iron(III). The precision, expressed by the relative standard deviation, and the accuracy, expressed as the relative error, are about 3-5%. Clinio Locatelli*, Francesco Fagioli, Tibor Garai, and Corrado Bighi, Department of Chemistry, University of Ferrara, Via Luigi Borsari 46, Ferrara 44100, Italy Anal. Chem., 60 {1988)
Further Developments in Photoacoustic Fourier Transform Infrared Spectroscopy: Temperature Studies 2408 Photoacoustic FT-IR measurements above room temperature provide useful information about the species adsorbed on the surface. Elevated temperatures do not influence the signal-to-noise ratio, which is maintained throughout the studied temperature region. Marek W. Urban*, North Dakota State University, Department of Polymers and Coatings, Fargo, ND 58105, and Jack L. Koenig, Case Western Reserve University, Department of Macromolecular Science, Cleveland, OH 44106 Anal. Chem., 60 (1988) Determination of Sodium and Potassium in Nanoliter Volumes of Biological Fluids by Furnace Atomic Absorption Spectrometry 2413
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 cylinders showed concentration losses ranging from < 1 % to >5%/year. Mean concentration change was -1.07%/year. Good agreement was found between CO loss and C02 formation. Eg, loss of CO of 0.188 ppmv/year was offset by C02 formation of 0.200 ppmv/year. The reaction was determined to involve various metal oxides on the inner surface of the cylinders. All the iron oxides
oxygen competed for active sites on the metal oxide surface, hindering adsorption of CO. When water was introduced into the system, FeO activity was reduced so CO loss was only 0.09%/year. Scott has developed unique cylinder wall treatments to reduce CO losses to
