1974 Volume 40 Issue 1 Pages 87-96
Basic research has been conducted concerning methods for the extraction and clean-up of test solutions containing N-dimethylnitrosamine (DMNA) to be analyzed by gas-liquid chromatography (GLC), and a series of recovery tests of DMNA added to fish-ham samples were carried out.
Results obtained may be summarized as follows:
1. DMNA in a fishery product can be extracted with CH2Cl2 under K2CO3 alkaline conditions when the extraction and separation by centrifugation are repeated 3 times at room temperature.
2. The concentration of a CH2Cl2 extract by rotary evaporation often cause a marked loss in DMNA recovery. However, it was found that under appropriate conditions more than 90% of DMNA could be recovered by rotary evaporation, the recovery being almost the same as the obtained with a Kuderna-Danish evaporative concentrator.
3. Clean-up of the CH2Cl2 extracts from fish roe products can be achieved by treatment with a strong cationic ion-exchanger, Amberlite CG-120 resion bufferized at pH 6.5, while those from fish-sausage and ham can be purified by HCl-treated Celite 545 column technique.
4. Recovery of DMNA added to fish-ham samples was found to be about 60% when analyzed according to the present procedures, and the reason for the low recovery rate might be attributable to the loss of DMNA occurring during the 3 steps of concentration of CH2Cl2 extracts in vacuum.
