Analysis of 2-alkylcyclobutanones with accelerated solvent extraction to detect irradiated meat and fish.

A new analytical procedure has been developed to analyze 2-alkylcyclobutanones to detect gamma-ray-irradiated fat-containing foodstuffs. Samples were extracted with an accelerated solvent extraction system via hot and pressurized ethyl acetate in cells. A large amount of fat in the extract was precipitated and removed with filtration by standing at -20 degrees C after the addition of acetonitrile. The extract was further cleaned with a 1 g silica gel mini column, and the radiolytic compounds of 2-docecylcyclobutanone (2-DCB) and 2-tetradecylcyclobutanone (2-TCB) were determined with gas chromatography with mass spectrometry (GC/MS). Sample preparation time before GC/MS was 7-8 h. At first, the procedure was evaluated with a recovery test in eight samples spiked with 2-DCB and 2-TCB at 20 ng/g, resulting in 70-105% recoveries with mostly less than 10% relative standard deviations. The procedure was further evaluated with beef, pork, chicken, and salmon samples irradiated with gamma-rays from 0.7 to 7.0 kGy at -19 degrees C. Both 2-DCB and 2-TCB in most samples were detected with good dose-response relations at all doses, while salmon was detected more than 2 kGy irradiation. The amounts of 2-alkylcyclobutanones produced reflected precursor fatty acids levels in samples, especially for the combination of 2-TCB and stearic acid. The results indicated that the production rate of 2-TCB to stearic acid was more obvious than that of 2-DCB to palmitic acid in frozen samples with gamma-ray irradiation.