ENVIRONMENTAL SCIENCE & TECHNOLOGY
ES&T
BRIEFS Chemical-Exchange and Paramagnetic h Relaxation Agents for Water Suppression in Spin-Echo Proton Nuclear Magnetic Resonance Spectroscopy of Biological Fluids 2885 Chemical exchange T 2 relaxation agents give efficient, reproducible water suppression in spin-echo proton NMR spectra of biofluids. Paramagnetic relaxation agents give irreproducible water suppression and severely distort NMR signals from biofluid metabolites. S. Connor and Jeremy K. Nicholson*, Department of Chemistry, Birkbeck College, University of London, London WC1E 7HX, U.K., and Jeremy R. Everett, Beecham Pharmaceuticals, Chemotherapeutic Research Centre, Brockham Park, Betchworth, Surrey RH3 7AJ, U.K. Anal. Chem., 59 (1987) Mechanisms of Graphite Furnace Atomization of Aluminum by Molecular Beam Sampling Mass Spectrometry 2891 Mechanisms that control atomization of aluminum and its modification by magnesium in the graphite furnace are investigated using molecular beam sampling and mass spectrometric techniques. D. L. Styris*, Pacific Northwest Laboratory, Richland, Wash. 99352, and D. A. Redfield, Northwest Nazarene College, Nampa, Idaho 83651 Anal. Chem., 59 (1987) Mechanisms Controlling Graphite Furnace Atomization and Stabilization of Beryllium 2897
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Real-time mass spectra of gas-phase species produced in a graphite furnace containing beryllium analyte and a magnesium modifier are used to elucidate the mechanisms that control vaporization, atomization, and stabilization. Comparisons are made with mechanisms associated with the atomization of aluminum. D. L. Styris*, Pacific Northwest Laboratory, Richland, Wash. 99352, and D. A. Redfield, Northwest Nazarene College, Nampa, Idaho 83651 Anal. Chem., 59 (1987) High-Temperature, High-Sensitivity Pyrolysis Field Ionization Mass Spectrometry 2903 Samples can be heated up to 800 °C using rates from 0.2 to 10 °C s _ 1 in a modified direct introduction system for pyrolysis field ionization MS. Mass spectra of biomaterials and synthetic polymers show molecular ions of building blocks up to m/z 2100. Hans-Rolf Schulten*, Fachhochschule Fresenius, Department of Trace Analysis, Dambachtal 20, D-6200 Wiesbaden, Federal Republic of Germany, and Norbert Simmleit and Rolf Millier, Institut Fresenius, Chemical and Biological Laboratories, D-6204 Taunusstein 4, Federal Republic of Germany Anal. Chem., 59 (1987) Continuous Solvent Extraction in a Closed-Loop System
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The on-line continuous solvent extraction system consists of a segmentor, an extraction coil, a phase separator, a switching valve, and a pumping system. The continuously pumped aqueous sample is merged with a fixed volume of organic solvent, which is recirculated for a selected number of cycles following separation to contact fresh solvent and provide preconcentration. Raja H. Atallah, Jaromir Ruzicka, and Gary D. Christian*, Center for Process Analytical Chemistry, Department of Chemistry, BG-10, University of Washington, Seattle, Wash. 98195 Anal. Chem., 59 (1987)
(800) 424-6747 1384 A · ANALYTICAL CHEMISTRY, VOL. 59, NO. 24, DECEMBER 15, 1987
