Determination of 17 Phthalates Plasticizers in Food by Gas Chromatography-Mass Spectrometry

Gas chromatography-mass spectrometry was applied to the determination of 17 phthalates (PAEs), which were proved to be harmful to human health, in 12 kinds of food. Pretreatment of the samples was carried out as described in GB 5009.271-2016. The sample was extractred ultrasonically with n-hexane at 30℃ for 30 min. For some samples (such as spinach, celery, mango juice and milk powder etc.) behaving to show high matrix effects, purification of the n-hexane extract by SPE on PSA/Silica glass column was performed and eluted as described in GB 5009.271-2016. The gas chromatography separation was modified by using the non-polar DB-5MS chromatographic column and selecting a lower initial temperature (60℃) and a lower rate of temperature elevation from 60℃ to 290℃, in order to have a better separation of the 17 PAEs. EI and SIM mode were adopted and the outer standard method for quantification was used in mass spectrometry determination. It was shown that linear relationships between values of mass concentration of the 17 PAEs and the respective peak areas were obtained in the same range of 0.05-2.0 mg·L^-1, with their detection limits (3S/N) ranged from 0.003 mg·L^-1 to 0.020 mg·L^-1. Recovery was tested by the standard addition method, giving values of recovery much higher than for those samples with complex matrixes (such as milk powder, vegetables and etc.) while for those samples with relatively simple matrixes (such as white wine, vinegar and etc.), giving values of recovery a slight extent over 100%. Values of RSDs (n=6) were found all less than 10%. On the base of analytical results of 12 food samples of various categories obtained by this method, the sources of the PAE-contaminators were mainly due to contacts with the plasticizers during their growth, production, transportation, packaging and etc.