Determination of volatile N-nitrosamines in meat products by microwave-assisted extraction coupled with dispersive micro solid-phase extraction and gas chromatography - Chemical ionisation mass spectrometry

A sensitive procedure, microwave-assisted extraction (MAE) coupled dispersive micro solid-phase extraction (D-mu-SPE), was developed to extract N-nitrosodimethylamine (NDMA) and other six volatile N-nitrosamines (NAms) from meat products. Parameters affecting the efficiency of MAE and D-mu-SPE were systematically investigated. For MAE, 5-g of a homogenised meat sample was extracted with 30 mL of a sodium hydroxide (0.025 M) solution at 100 degrees C for 10 min. The optimum D-mu-SPE conditions were immersing 100 mg of Carboxen (TM) 1000 adsorbent in the MAE extract. After vigorously shaking for 30 min, the NAms were then desorbed by treatment with 200 mu L of dichloromethane. A 10 mu L aliquot was determined by gas chromatography with chemical ionisation mass spectrometry (GC-CI-MS) using the selected-ion-storage (SIS) mode. The limits of quantitation (LOQs) were 0.03-0.36 ng/g. Preliminary results revealed that NDMA was present in the highest concentration, ranging from 0.8 to 3.2 ng/g. (C) 2012 Elsevier Ltd. All rights reserved.