A spin-trapping database implemented on the IBM PC/AT

Abstract

Spin trapping is a technique in which highly reactive free radicals are detected by reaction with a diamagnetic molecule (usually a nitrone or nitroso compound) to form more stable free radicals (spin adducts) that can be observed by conventional electron spin resonance spectroscopy (1). Since its inception in 1969, spin trapping has gained wide acceptance in the study of short-lived reactive free radical species generated in chemical reactions, as well as in biochemical and biological systems (26). More recently, the technique has been employed to detect free radicals in isolated organs and intact animals (7, 8). The breadth of spin-trapping applications ranges from the undergraduate physical chemistry laboratory (9) to high-energy physics (IO). The number of useful spin traps has also increased and now includes compounds such as unsaturated substituted alkanes (10) and quinones (1 I). At present, Chemical Abstracts lists nearly 1000 references that contain the key word “spin trap(ping).” Unfortunately, abstracts often do not contain the ESR parameters of the spin adducts and other such useful information. Even if these data are present, it is usually necessary to consult the full publication for the experimental conditions, since ESR parameters are known to be system dependent (12). Buettner (2) has recently published a list of spin adducts derived from DMPO,’ PBN, MNP, and other popular spin traps. Each entry contains the type of adduct( the solvent system, the ESR parameters, experimental information, and reference. This compilation is very useful for finding the range of hyperfine parameters for a known adduct. However, in order to search for spin adducts with a given set of hyperfine parameters, obtained under defined experimental conditions, it is necessary to peruse the entire list. This approach is similar to trying to find an address in a telephone book using only a telephone number. The chore of manually searching a vast amount of printed information, plus the inflexibility in arranging such information, warrants the use of a computer. For information retrieval purposes a computer system is much less tedious, less time consuming, and less error prone than a paper-based system.