| The major oxidation products of ethoxyquin (EQ, 1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline) in fish meals, fish feeds and farmed fish were studied. Two new HPLC methods were developed for quantitative determination of these compounds.; When EQ was added to a freshly produced, antioxidant untreated herring fish meal, a quinone imine (QI, 2,6-dihydro-2,2,4-trimethyl-6-quinolone) and a dimer (DM, 1,8{dollar}spprime{dollar}-di(1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline)) were found to be the major oxidation products during storage at room temperature.; Several methods were investigated to purify EQ, QI and DM as the standards for quantitative determination.; To determine EQ, QI and DM in fish meal or fish feed, the sample was first extracted with hexane. After the removal of hexane, the three analytes were extracted from the resulting oil with acetonitrile and determined by C18 reversed phase HPLC with a UV detector set at {dollar}lambda{dollar} = 280 nm.; The probable occurrence of DM in the liver and muscle of farmed salmon and steelhead was confirmed by GC-MS, and it was then quantitatively determined by HPLC analysis. (Abstract shortened by UMI.)... |
