1994 Volume 35 Issue 4 Pages 385-389_1
A method for the quantitative determination of trace amounts of tetramethylsuccinonitrile (TMSN) released into foods from their plastic containers is described. TMSN is a decomposition product of 2, 2′-azobisisobutyronitrile used as a polymerization initiator for monomers in plastic production. TMSN in 50g (or ml) of food is steam-distilled. The distillate, to which nitrobenzene has been added as an internal standard, is shaken with 50, 30 and 30ml of methylene chloride for extraction of TMSN. The combined solvent layers are concentrated to 5-7ml by a rotary evaporator, and to 1ml with a nitrogen gas stream. The concentrate is washed 3 times with 1ml of 6N hydrochloric acid. The solvent layer is dried with 1g of anhydrous sodium sulfate. The final step consists of gas chromatography using a 180cm column of 5% Thermon 1000 and 0.5% phosphoric acid on Chromosorb W and a nitrogen-phosphorus detector. The limit of detection was 1μg/kg or μg/L. Recoveries of TMSN ranged from 94.0 to 104.2% at levels of 10-20μg/kg. The method was applied to 9 kinds of foods packed or bottled in containers made of plastics. No interfering substances were observed on the gas chromatograms.
