Presence of phthalates in contact lens and cleaning solutions

A fast and simple method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been applied to identify and quantify four phthalic acid esters (PAEs) in different contact lens cleaning solutions. A migration study of these compounds from contact lenses has also been performed. The PAEs studied were dimethyl phthalate, diethyl phthalate, butyl benzyl phthalate and dibutyl phthalate. The migration of PAEs from contact lenses was performed by suspending each contact lens in an artificial tear solution at 37 °C and shaking it at 130 rpm for 24 h. The purpose of this study was to determine a possible migration of these compounds to the eyes as a result of the use of contact lenses and their cleaning solutions. The method was precise (with relative standard deviation (RSD) from 2.2 to 11.9%). It was also sensitive, with LODs of 0.03, 0.19, 0.31 and 2.62 μg L^− 1 for DMP, DEP, BBP and DBP respectively. The results obtained confirm the presence of these substances in some types of contact lens cleaning solutions. Furthermore, DBP and BBP were liberated from the contact lenses during the migration study.