Analysis of volatile nitrosamines from a model system using SPME–DED at different temperatures and times of extraction

Solid-phase microextraction (SPME) coupled to a direct extraction device (DED) was evaluated as a method for extracting nitrosamine (NA) standard mix containing nine volatile nitrosamines from a solid food model system using several temperatures and times of extraction. The efficacy of extraction, the linearity of response and the sensitivity of this method for analysis of NA were determined at refrigeration (4 °C) and room (25 °C) temperature. Several extraction times (15, 30, 60,120 and 180 min) were also tested. Analysis was carried out with gas chromatography–mass spectrometry (GC–MS) in selected ion monitoring (SIM) mode. At 4 °C all NA were detected at all concentrations studied (ranged from 1 to 50 ng ml−1) except for N-nitrosopyrrolidine (NPYR), N-nitrosomorpholine (NMOR) and N-nitrosodiphenilamine (NDPheA). Better results were obtained at 25 °C in terms of efficacy of extraction, linearity values (regression coefficients, R2) and sensitivity values (limit of detection, LOD). Only 15 min of extraction time were enough to extract all NA from gelatines (10 ng ml−1) at 25 °C. None of the NA reached the equilibrium, even when long times of extraction (20 and 24 h) were evaluated. SPME–DED appears to be a rapid and suitable technique for extracting NA from model food system at both refrigeration and room temperatures.