Method Development for Trace Level Detection of N-Nitrosamines in Beer by GC-MS/MS

A MRM method that simultaneously analyse six different N-nitrosamines, namely N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosodibutylamine (NDBA), N-nitrosopyrrolidine (NPYR), N-nitrosomorpholine (NMOR) and N-nitrosopiperidine (NPIP) was developed. N-nitrosodipropylamine (NDPA) was used as the internal standard (ISTD). Satisfactory linearity was obtained for each target analyte. All the correlation coefficients (R2) across calibration standard solutions in the range of 0.1 ppb - 50 ppb were greater than 0.999. The relative standard deviation (%RSD) which indicates the injection-to-injection repeatability and consistency of results for the target analytes was within 10% for solution concentration in sub-ppb level. The LOQ of the N- nitrosoamines were determined to be in low ppb level using standard solution. Therefore, it is possible to utilize the above stated sample preparation method (10 times concentration of the sample) coupled with GC-MS/MS for the analysis of sub-ppb level of N- nitrosoamines in beer samples.