## 3 Results and Discussion
### Identification of Non-Volatile Compounds by UHPLC-Q-TOF-MS  
The chromatograms of the TPS/PBAT film sample extraction, conducted as described in Section 2.3 and obtained using UHPLC-Q-TOF-MS, are presented in Figure 2. Structural elucidation of the detected peaks was performed using UPLC-Q-TOF-MS analysis by examining the mass spectra of each peak to determine their molecular composition. High-resolution mass measurements allowed for precise identification through the analysis of fragmentation patterns and isotopic distributions. The experimentally obtained masses were compared against entries in the ChemSpider chemical database to propose potential molecular structures [19]. Additionally, the mass spectra were cross-validated with previously reported data in the literature from [PERSON] et al. [32], [PERSON] et al. [34] to confirm consistency with known compounds. Table 3 lists the non-volatile compounds identified in the total dissolution of PBAT resin, PBAT film, and TPS/PBAT with and without food preservatives, namely sodium nitrite (N), sodium erythorbate (E), sodium tripolyphishe (T), sodium hexametaphosphate (H), and tetrasodium pyrophosphate (P). Most of the ten detected compounds, classified as NIAS, were cyclic compounds derived from adipic acid (AA), 1,4-butanediol (BD), and terephthalalic acid (TPA) [19; 22; 34; 35]. These are PBAT-derived oligomers, some of which were also identified via GC-MS, which likely originate as by-products from raw PBAT resin, formed during the polycondensation process of polyester synthesis. This is supported by the higher mass intensities observed in PBAT samples compared to TPS/PBAT, as shown in Figure 3. The intensities of these compounds decreased progressively throughout the manufacturing process, likely due to degradation caused by thermal processing during blown-film extrusion. PBAT film are subjected to a single extrusion step, whereas TPS/PBAT film undergo three heating stages--two during pellet preparation and one during film blowing--resulting in a more pronounced reduction in compound intensity [3; 33; 22; 35]. Additionally, the incorporation of food preservatives introduced new compounds, including methyl phenylglyoxylate(4.69_165.0552), triacetin (5.13_203.0919), and resorcinol (6.08_111.0446), which function as curing agents, surface modifiers, and linking agents, respectively. These findings indicate that both thermal processing and the incorporation of preservatives significantly alter the chemical composition of TPS/PBAT films, potentially impacting their functionality and safety [36]. A thorough understanding of these changes is essential for optimizing film performance and ensuring their compliance with food packaging safety requirements, particularly in terms of chemical stability and migration behavior. Figure 3: Intensity of the non-volatile components of PBAT resin, PBAT film, and TPS/PBAT with and without food preservatives, namely sodium nitrite, sodium erythorbate, sodium tripolyphosphate, sodium hexametaphosphate, and tetrasodium pyrophosphate films. Significant differences are indicated by different letters. Figure 2: Chromatogram obtained by UHPLC-Q-TOF-MS analysis of TPS/PBAT film. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c c c} \hline \hline
**No** & **Rt** & _m/z_ & **Adduct** & \begin{tabular}{c} **Molecular** \\ **Formula** \\ \end{tabular}