Rapid determination of nine N-nitrosamines in dry-cured mackerel (Scomberomorus niphonius) using salting out homogeneous phase extraction with acetonitrile followed by GC-MS/MS

Abstract

N-nitrosodimethylamine (NDMA), belonging to N-nitrosamines (NAs), was detected in several batches of aquatic products in Guangdong, China in 2019, making it urgent to monitor their contamination levels. A salting out homogeneous extraction coupled with GC-MS/MS method was developed for trace analysis of nine NAs in dry-cured mackerel. Results indicated calibration curves were linear from 0.5 to 200 μg/L with R2 higher than 0.9998. LODs and LOQs were in the range of 0.08–0.15 and 0.25–0.5 μg/kg, respectively. Matrix effects ranged from 0.98 to 1.17, which is within the commonly acceptable range. Favorable recoveries (77.1–112.9%) were obtained with RSDs below 7.4%. The proposed method shows rapid extraction time and favorable LODs, recoveries and RSDs which are comparable with other methods. The method was successfully applied for NAs determination in dry-cured mackerel, NDMA is widely detected in all samples with the concentration of 5.3–71.4 μg/kg and almost all kinds of NAs were detected in one sample.