Phthalic Acid Esters Released in Infused Drinks: Analytical Issues Related to their Determination

Phthalates (phthalic acid esters, PAEs) are a group of xenobiotic substances widely used in the production of plastic due to their ability to make it softer and more workable [1]. These chemical compounds are also used in the production of containers for the consumption of food beverages, in particular hot drinks dispensed by automatic vending machines. High temperature could facilitate the migration of PAEs from the plastic container to the infused drinks [2]. This work aims at developing a simple and reproducible analytical methodology for the extraction and determination of traces of PAEs from infused drinks. The extraction methodology is based on the solid phase extraction (SPE) coupled with GC-MS for their determination. A preliminary phase is focused on the study of the most appropriate stationary phase between the C18 cartridge and Carbograph 1 by means of adsorption isotherms. The best interaction with the investigated analytes is shown by the C18 sorbent. The method development is based on the construction of breakthrough curves in order to individuate the best working conditions and on the choice of the best extraction solvent. Heptane showed the best recoveries (76.6 – 105.5 %) with a relative standard deviation < 8.3%. For the validation of the methodology, all the analytical parameters are investigated: LODs and LOQs (respectively 0.018 – 0.120 μg mL-1 and 0.082 – 0.130 μg mL-1), reproducibility, accuracy and precision. The overall methodology is applied to real samples such as coffee (espresso and decaffeinated espresso), ginseng coffee and tea: the results shown the presence, in low concentrations, of PAEs in infused drinks.