Determination of benzophenone and related compounds in plastic packaged baby food by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry†
Benzophenone and its derivatives (BPs) are commonly used as photoinitiators in UV-inks and as additives in plastic food packaging. However, most of these substances, which have shown endocrine disrupting effects, can migrate from plastic materials into food. In this work, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method has been developed to monitor 17 BPs in fatty baby food in less than 13 min. To obtain the maximum sensitivity, electrospray ionization was performed in both positive and negative ion modes. Tandem mass spectrometry fragmentation was studied to propose a fragmentation pathway and to select the most characteristic and abundant product ions for both quantitation and confirmation purposes in the multiple reaction monitoring (MRM) mode. The UHPLC-MS/MS method was applied for the analysis of BPs in yogurt, custards and chocolate products and dispersive solid phase extraction (dSPE) using an Enhanced Matrix Removal-Lipid (EMR-Lipid) sorbent was developed as a clean-up and pre-concentration step. The quality parameters demonstrate the good performance of the proposed method, providing limits of quantitation (1–50 μg kg−1) below the legislated migration limit for BP (SML[BP] = 600 μg kg−1), extraction efficiencies higher than 70% and matrix effects below 30% for most of the BPs, although for the chocolate product the matrix effect rose up to 55%. BPs were monitored in 27 fatty baby food samples using matrix-matched calibration for the quantitative analysis and among the analyzed samples, MBB and PBZ were detected in one of them at a concentration level below the SML[BP].