Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta Ion mobility quadrupole time-of-fight mass spectrometry for the identifcation of non-intentionally added substances in UV varnishes applied on food contact materials. A safety by design study E. Canellas a , P. Vera b , C. Nerín b,∗ a Samtack Adhesivos Industriales, C/ Cerámica, nº3, Pol. Ind. Magarola Sud, 08292, Esparreguera, Barcelona, Spain b GUIA Group, Department of Analytical Chemistry, University of Zaragoza, I3A, María de Luna,3, 50018, Zaragoza, Spain ARTICLE INFO Keywords: IM-HRMS E NIAS Food contact UV varnish ABSTRACT Varnishes are normally applied on printed food packaging to protect it from smearing and scratching. Moreover, they may be applied on the food contact surface in order to improve resistance towards moisture and fat. Some of the compounds that make up the varnish formulation could migrate to the food. In this work, the ion mobility quadrupole time-of-fight mass spectrometry has been used to obtain drift time-aligned mass spectra in which accurate the mass of precursor ions and their fragments are used to identify both intentionally and non-in- tentionally added substances (NIAS). The compound 2-propenoic acid,1,1'-[2-[[3-[2,2-bis[[(1-oxo-2-propen-1- yl)oxy]methyl]butoxy]-1-oxopropoxy]methyl]-2-ethyl-1,3-propanediyl] ester was identifed as a NIAS formed from the varnish monomer 2-propenoic acid, 1,1'-[2-ethyl-2-[[(1-oxo-2-propen-1-yl)oxy]methyl]-1,3-propane- diyl] ester. The compound 5, 11-diethyl-7-oxo-4,6,10,12-tetraoxopentadecane-3,13-diyl diacrylate is a NIAS derived from the varnish monomer 2-propenoic acid, 1,1'-[oxybis(methyl-2,1-ethanediyl)] ester, and was found to migrate into the food simulant tested at a level of 0.03 mg kg −1 . Finally, the NIAS, 2-{2-[2-(acryloyloxy)-1- methylethoxy]-1-methylethoxy}-1-methylethyl acrylate, an impurity of a photoinitiator used for UV curing of the varnish, was identifed, and its migration of 0.14 mg kg −1 exceeded the threshold established as safe for human consumption. 1. Introduction Varnishing is a fnishing process used in food packaging where a thin transparent layer of varnish is applied on the printed material. In this way, the print is protected from smearing and scratching, and the surface is glossier and even. Varnishes are a kind of ink without col- orant [1] and may be applied to the food contact surface in order to improve resistance towards moisture and fat [2]. UV varnishes contain reactive resins that polymerize and form a hard flm under UV radia- tion. The main components are oligomers, monomers, prepolymers and photoinitiators [3]. Therefore, all these components are susceptible of migration from the packaging to the food in contact with it. When the varnish is applied over the printed surface, several migration mechan- isms can occur, such as a) the direct migration, that is the transfer of matter from the printed side through the substrate onto the unprinted internal side, and b) the set of, where the compounds can be trans- ferred to the internal food contact non printed layer due to its contact with the external printed surface, when the printed material is stored as reels. In the case of photoinitiators, there are many works that studied these migration phenomena [4–6]. Nevertheless, a lot of work has still to be done in the area of non-intentionally added substances (NIAS). NIAS are originated from impurities, oligomers reaction by-products or degradation processes [7]. The phenomenon of NIAS were specifcally mentioned in Article 19 of Regulation EU 10/2011 [8], then it has been studied in several areas of packaging such as paper and board [7], plastic materials [9], coatings [10,11], adhesives used for multilayer [12–15] and labels [16,17]. As it can be seen in these works, the study of NIAS is an analytical challenging work, where a wide series of un- knowns can appear. Thus, high resolution mass spectrometry coupled to efcient separation techniques are required. Ion mobility mass spectrometry (IMS) is a gas-phase technique whose mechanism relies on the separation of ions with diferent mo- bility that pass through a drift cell in which a constant electric feld is applied [18]. The ions are characterized by their collision cross-section value (CCS), a parameter related to the ion's rotationally averaged size, shape, total charge and charge distribution. Depending on the gas used, https://doi.org/10.1016/j.talanta.2019.06.103 Received 23 May 2019; Received in revised form 27 June 2019; Accepted 28 June 2019 ∗ Corresponding author. E-mail addresses: elenacanellas@samtack.es (E. Canellas), pvera@unizar.es (P. Vera), cnerin@unizar.es (C. Nerín). Talanta 205 (2019) 120103 Available online 29 June 2019 0039-9140/ © 2019 Elsevier B.V. All rights reserved. T