Further inveatigations are underway since it is important to know whether the reaction between acyl hydroperoxides (peracids) and nitrones is general. This molecular reaction may have significant impact on the use of spin traps in biological systems. ... Acknowledgment. The authors recognize the financial support for a studentship for C.-RL provided by the National Taiwan University and facilitated by Prof. T.4. Ho. Assistance in this work from Dr. Y. Kotake is also gratefully ...