Determination of 15 Kinds of N-nitrosamines Residues in Plastic Children’s Toys by GC-MS/MS

A method for the determination of 15 N-nitrosamines residues in ABS and PVC plastic toys was developed based on dissolution precipitation-gas chromatography-tandem mass spectrometry (GC-MS/MS). After dissolving in the corresponding solvent and precipitating with methanol, the plastic toy samples were centrifuged at 13 000 r/min for 5 min at 4 ℃. The supernatant was collected and then detected by instrument after filtered through 0.22 μm membrane. The analytes were separated by DB-17MS column, scanned by multiple reaction monitoring (SRM), and quantified by external standard method. The results of recovery of self-made positive samples showed that the dissolution precipitation method had a high extraction rate. GC-MS/MS had strong selectivity, impurity peaks in samples did not interfere with the detection of N-nitrosamines. Due to the solvent effect and matrix effect, the standard curve matched with blank sample matrix was needed for quantitative analysis. The limits of quantification (LOQs) for different substances were 0.02-0.2 mg/kg, and the linear ranges were 0.02-20 mg/kg with the correlation coefficient (R²) greater than 0.996 3. The recoveries of N-nitrosamines in ABS and PVC samples ranged from 77.6% to 126.2% and 75.6% to 122.4%, respectively. The relative standard deviation (RSD, n=6) ranged from 1.7% to 8.7% and 1.4% to 10.2%, respectively. Finally, the method was applied to the actual samples of 35 ABS toys and 30 PVC toys sold in the market, and no N-nitrosamines were detected. The method is simple, rapid, accurate and sensitive. It is suitable for the determination of 15 N-nitrosamines residues in two kinds of plastic toys.