Following the recent prohibition on the use of BPA for the production of polycarbonate (PC) baby bottles in the European Union, baby bottles made of alternative materials, such as polypropylene, polyethersulphone, polyamide, Tritan™ or silicone, have appeared in the market. An initial study done in previous work applying a liquid-liquid extraction (LLE) followed by GC-MS analysis identified a wide variety of migrating compounds. Based on these screening results, the monitoring and quantification of the most important migrating compounds was further pursued. We describe the optimisation, validation and application of an LLE method for the extraction of these migrating compounds adapted to low concentrations. Generally, absolute recoveries between 70 and 110 % with RSDs < 20 % were obtained. Further, specific and quantitative GC-QqQ-MS and LC-QqQ-MS methods were developed and validated by evaluating the following parameters: sensitivity, selectivity, linearity, accuracy, precision, recoveries and matrix effects. Limits of quantification (LOQs) ranged between 0.6 and 8 μg kg−1 for the majority of the selected compounds. Linearity ranged using Mandel’s fitting test between coefficients of determination (R 2) of 0.995 and 0.999. Both repeatability and reproducibility were demonstrated to be satisfactory considering the Horwitz equation. Finally, the methods were applied on a selection of baby bottles representative for the Belgian market. Several compounds previously identified by the screening approach were confirmed and adequately quantified. For instance, azacyclotridecan-2-one had a maximum migration value of 1091 μg kg−1 whereas 4-propylbenzaldehyde migrated at 27 μg kg−1 and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB) at 348 μg kg−1. However, most of the targeted compounds were not detected or below the LOQ.