Determination of phthalates in raw bovine milk by gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS) and dietary intakes

Abstract

Low levels of phthalates, including di(2-ethylhexyl) phthalate (DEHP), in raw bovine milk were determined using gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS). A fast and convenient process of sample treatment combined with TOF-MS analysis (medium resolution >5000), yielded good recoveries (85–125%) and low limits of detection (<0.002 mg kg⁻¹). The most commonly used phthalate, DEHP, was found in 15 out of 30 samples monitored in this study. DEHP concentrations in raw milk ranged from not detected to 0.154 mg kg⁻¹, and the mean concentration was 0.057 mg kg⁻¹. The dietary intake of DEHP was about 0.004 mg kg⁻¹ body weight day⁻¹ if a child (24 months, 13 kg body weight) drinks 1 L day⁻¹ of milk that contains the mean concentration of DEHP found in raw milk. The estimated dietary intake corresponded to 8% of the European Union tolerable daily intake (TDI) of 0.05 mg kg⁻¹ body weight day⁻¹. Dimethyl phthalate (DMP) and di-n-butyl phthalate (DBP) were found from two and 20 samples, respectively, at low levels. Diethyl phthalate (DEP), butylbenzyl phthalate (BBP), and di-n-octyl phthalate (DnOP) were not found in any of the samples.

Keywords:

• phthalates
• di(2-ethylhexyl) phthalate (DEHP)
• milk
• dietary intake
• gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS)