Measurement of Hexanal Production by Myoglobin-Induced Lipid Peroxidation Using a Miniature Incubator and Cryofocusing Inlet System with Gas Chromatography and Time-of-Flight Mass Spectrometry

摘要

A miniature incubator was used in combination with a cryofocusing inlet system and GC-TOFMS in order to determine the rate of hexanal production during myoglobin (Mb)-induced lipid peroxidation of phosphatidyl choline containing arachidonic acid. The cryofocusing inlet system allowed for rapid preconcentration of the volatile products of the peroxidation reaction, yielding a total analysis time for hexanal of less than 4 min. Each reaction was sampled repetitively, and the production of hexanal was determined in real time, as the reaction progressed. Myoglobin-induced lipid peroxidation produced hexanal linearly over 40 min, maximizing at an average concentration of 1 ppm after 60 min. In reaction mixtures containing basal levels of hexanal, presumably due to autoxidation occurring during storage, greater amounts of hexanal were formed at a faster rate of production, though the production was not linear for more than 15 min. The rapid preconcentration and nondestructive sampling are advantageous; the sampling time can be adjusted in order to detect and quantitate minor products, and the instrumentation can thus be used for full profiling of the volatile products of lipid peroxidation.