Metal Analysis by Gas Chromatography of Chelates of Heptafluorodimethyloctanedione

Abstract
The synthesis, characterization, and gas chromatography of some new metal complexes of 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedione are described. The chelates of iron(III), nickel(II), palladium(II), chromium(III), copper(II), aluminum(III), yttrium(III), and beryllium(II) can be eluted without apparent decomposition. It was discovered that the neat ligand reacts directly and rapidly at elevated temperature with a large number of metals, metal compounds, alloys, and ores. This discovery led to the development of a new simple technique for microanalysis of metals by gas chromatography of the metal fluorocarbon β-diketonates formed. The sample was weighed in a glass capillary tube sealed at one end, an excess of the ligand was added, the tube was sealed and heated, and then crushed in the injection port of the gas chromatography apparatus. The total sample required for quantitative analysis is less than one-tenth of a milligram. The efficacy of the technique was demonstrated by the microanalysis of a National Bureau of Standards sample of Mesabi iron ore. The ligand quantitatively dissolves fourteen of the metals studied, the reaction in some cases being apparently water catalyzed. As a consequence of this extraordinary reactivity, the sample preparation procedures previously used can be greatly simplified for many types of samples by eliminating the solvent extraction operations. The simplification, in addition to saving time and manipulative effort, should facilitate automation of micro-analysis.