Microwave mediated distillation with solid-phase microextraction: determination of off-flavors, geosmin and methylisoborneol, in catfish tissue

Presented is a rapid distillation device for use with solid-phase microextr action (SPME). We apply this device specifically for determining two semivo latile off-flavor compounds, methylisoborneol and geosmin, in channel catfi sh. The presence of these two compounds in channel catfish filets results i n unwelcome tastes. In the presented procedure, a catfish tissue sample is placed within a sample container located inside the microwave device. Micro wave radiation is applied and distillates formed migrate through a condense r via a purge gas and are collected in a sample vial. A SPME fiber is place d within the stirred collected distillate and methylisoborneol and geosmin are extracted. Qualitative and quantitative results of these extractions ar e obtained using a gas chromatograph-ion trap mass spectrometer. This solve ntless technique results in detection limits far below the human threshold for these off-flavor compounds in channel catfish. (C) 1999 Elsevier Scienc e B.V. All rights reserved.