2. Materials and methods2.1. Contents of NAs in processed meat productsResults from a recently performed survey on the occurrence of NAs in 70 samplesof processed meat products available on the Danish market were applied for the exposureassessment. Details on this study are described elsewhere (Herrmann et al.,2014a). The NA contents of the samples were determined using a recently developedmethod allowing for the quantification of eight VNAs and five NVNAs (Herrmannet al., 2014b). In brief the homogenized samples (2.5 g) were extracted with acidi-fied acetonitrile (7.5 ml with 1% formic acid). After centrifugation the clear supernatantwas frozen, defrosted and centrifuged again. An aliquot was concentrated by a factorof five under a gentle stream of nitrogen. An aliquot was mixed 1:1 with Milli-Qwater, filtered and analyzed by LC (APCI/ESI)-MS/MS. The chromatographic separationwas performed on an Agilent 1200 Series HPLC (Agilent Technologies, SantaClara, CA, USA) with a Poroshell PhenylHexyl 150 × 2.1 mm, 3 μm column (AgilentTechnologies) using water and methanol both with 0.1% formic acid as mobile phase.The MS/MS detection was performed on an Agilent 6460 Series Triple Quadrupole(Agilent Technologies) equipped with either an APCI or a Jet Stream ESI source. Thequantitative and qualitative analyses were performed by external calibration andcomparing retention times and quantifier ion/qualifier ion ratios obtained by analyzingNA standard solutions and spiked QC samples and comparing with the samples.The LOQs obtained with the described method were generally <1 mg kg−1, thoughwith some exceptions for specific NA/meat product combinations. The validationresults are presented in detail in Herrmann et al., 2014b.The results of the survey are presented as the mean content in Table 2. Both themean of all positive findings as well as the mean of all samples analyzed are presented.The latter mean values are the values applied for the exposure assessment.The non-detects were in this case set to zero.
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