Analysis of new pollutants p -phenylenediamine (PPD) antioxidants and PPD-quinones in PET bottled drinks and packaged snacks from supermarket using LC-MS/MS

The extensive use of p-phenylenediamine (PPD) as commercial antioxidants has led to considerable environmental pollution of PPDs and their oxidative derivatives PPD-quinones (PPD-Qs). The broad presence of toxic PPDs and PPD-Qs in air, water and soil caused nonnegligible human health risks. In contrast to environmental exposure, taking food is a more direct route for harmful organic substances entering human body. However, limited works investigate PPDs and PPD-Qs in food. In this work, a method using liquid chromatography-tandem mass spectrometry was developed to determine PPDs and PPD-Qs in commercial PET bottled drinks and packaged snacks bought from supermarket with high sensitivities (method detection limits <0.12 pg/mL for drinks and <3 pg/g for snacks), acceptable recoveries (72–117%) and satisfactory precisions (relative standard deviations of 1–15%). The detection results indicated wide appearance of these emerging pollutants in drinks and snacks. Of note, the total concentrations of PPDs (n.d. −62 ng/mL) and PPD-Qs (0.02–11 ng/mL) revealed more serious pollution in PET bottled drinks than in surface water. For packaged snacks, PPDs and PPD-Qs had total concentrations ranging from n.d. to 3 ng/g and from n.d. to 48 ng/g, respectively. N,N’-di(o-tolyl)-p-phenylenediamine (DTPD), DTPD-quinone (DTPD-Q) and N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone (6PPD-Q) had relatively high frequencies of appearance in packaged snacks. Calculation of estimated daily intakes of PPDs and PPD-Qs in PET bottled water and packaged snacks further pointed out their potential exposure risks for adults and children, suggesting their occurrence in food and associated adverse health effects should not be underestimated.