Caprolactam and 2,4-di-tert-butyl phenol (2,4-DTBP) are substances typically found in some food contact materials (FCMs). They are known to often migrate into food, and are difficult to analyse in liquid food simulants using GC. In this work a simple salting-out Liquid-Liquid Extraction (SALLE) for the analysis of both substances in water and the official food simulant A (10 % v/v ethanol, Regulation (EU) No. 10/2011) is presented. The method, which included analytical determination by GC-MS, was optimized and validated to ensure sufficient analytical quality.

The method’s LOQs allowed the proper quantification of caprolactam at its EU legislative limit (15 mg kg⁻¹). For 2,4-DTBP the method also revealed good sensitivity, although no official limits have been established yet. Linear regression coefficients (R²) were in all cases higher than 0.999, and recoveries ranged from 87 % and 95% for caprolactam and 2,4-DTBP, respectively. Precision was also acceptable, with the RSDs (%) below 12 %. The method proved to be adequate to be used for routine analysis.

The presence of salt during migration of caprolactam and 2,4-DTBP was also investigated in this work. Polyamide/polyethylene FCM multilayer films have been tested with water and simulant A, containing different amounts of NaCl (up to 15 % m/v), and applying different migration conditions (temperature and time). The results indicated that salinity plays an important effect on the migration of caprolactam, with the presence of salt reducing its migration in case of water and increasing it in case of simulant A. These preliminary results seem to indicate that migration testing should consider not only the well-known fatty content of a food, but also its salinity content, as it may end up affecting drastically the migration of polar substances.

己内酰胺和2,4-二叔丁基苯酚（2,4-DTBP）是一些食品接触材料（FCM）中常见的物质。众所周知，它们经常迁移到食品中，并且很难使用GC在液态食品模拟物中进行分析。在这项工作中，提出了一种简单的盐析液提取（SALLE），用于分析水中的物质和官方食品模拟物A（10％v / v乙醇，法规（EU）第10/2011号）。该方法（包括通过GC-MS进行分析测定）已经过优化和验证，以确保足够的分析质量。

该方法的最低定量要求允许在其欧盟立法限值（15 mg kg ^-1）下正确定量己内酰胺。对于2,4-DTBP，该方法也显示出良好的敏感性，尽管尚未建立正式的限制。在所有情况下，线性回归系数（R ²）均高于0.999，己内酰胺和2,4-DTBP的回收率分别为87％和95％。精度也可以接受，RSD（％）低于12％。事实证明该方法足以用于常规分析。

在这项工作中还研究了己内酰胺和2,4-DTBP迁移过程中盐的存在。聚酰胺/聚乙烯FCM多层膜已经用水和模拟物A进行了测试，其中包含不同量的NaCl（最高15％m / v），并且应用了不同的迁移条件（温度和时间）。结果表明，盐度对己内酰胺的迁移有重要影响，盐的存在降低了水的迁移，而模拟物A则增加了盐的迁移。这些初步结果似乎表明迁移测试不仅应考虑食品中众所周知的脂肪含量以及盐分含量，因为它最终可能会严重影响极性物质的迁移。