Determination of N-nitrosodimethylamine in beer by gas chromatography-stable isotope dilution chemical ionization mass spectrometry
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文摘
A sensitive method for the determination of N-nitrosodimethylamine in beer samples is described. The analyte was isolated by distillation and subsequent extraction from the distillate using dichloromethane. Analysis was carried out by gas chromatography combined with positive-ion chemical ionization mass spectrometry. Quantification was performed by stable isotope dilution using [2H6]-N-nitrosodimethylamine as the internal standard. The measurements exhibited excellent linearity in the range 0.10-4.00 μg kg−1 (r = 0.99999) and a detection limit of 0.04 μg kg−1 was achieved. The between-sample relative standard deviation of the method was 0.73 % (n = 5) at a concentration level of 0.86 μg kg−1. The recovery of the compound was 78 ± 2.1 % . The proposed procedure seems to be a good alternative to the frequently used gas chromatography-thermal energy analysis approach for the determination of N-nitrosodimethylamine.