Determination of phthalate diesters and monoesters in human milk and infant formula by fat extraction, size-exclusion chromatography clean-up and gas chromatography-mass spectrometry detection

摘要

Graphical abstract Display Omitted Highlights ? A method for the analysis of phthalate diesters and monoesters in milk is proposed. ? Phthalate monoesters and diesters were analysed in breastmilk and infant formulas. ? Target analytes were found to be present in all the investigated samples. ? Phthalate contamination was higher in infant formula than in breast milk. ? Daily intake of phthalates was lower than MADI established by EU-CSTEE and EU-SCF. Abstract A sensitive and reliable analytical method was developed for the simultaneous determination of five phthalate diesters and corresponding monoesters in human milk samples and infant formulas. The method involved a liquid–liquid extraction with a CH 2 Cl 2 /CH 3 OH/NaCl 30% 2/1/0.5 ( v/v/v ) mixture, the clean-up of the extract by size-exclusion chromatography (swelling and elution solvent: cyclohexane/ethyl acetate 9/1 v/v ), the derivatization of monoesters by trimethylsilyl-diazomethane and instrumental analysis by gas chromatography coupled with mass spectrometry. Recovery was in the range of 83–115% and precision was found between 9% and 21%. For phthalate diesters, method detection limits (MDLs) ranged from hundreds of ng/kg to 4.2μg/kg on a fresh weight milk (f.w.) basis, depending on blank contribution evaluated in matrix. Lower MDLs (0.03-0.8μg/kg f.w.) were achieved for corresponding monoesters. The proposed method was applied to the determination of target compounds in nine human milk samples and four infant formulas, confirming their presence in all samples. However, a generally higher contamination was assessed in artificial milk than in breast milk samples.