An analytical method for the determination of silver in food simulants (3% (w/v) aqueous acetic acid or 95% (v/v) aqueous ethanol) was developed based on inductively coupled plasma mass spectrometry (ICP-MS). Recoveries ranged from 87% to 109% and RSDs ranged from 0.7% to 7.8%. The procedure was applied to determine the migration of silver from nanosilver-polyethylene food packaging film into food simulants at different temperatures and migration times. Results indicated that the maximum migration ratios were 1.70%, 3.00% and 5.60% for 3% (w/v) aqueous acetic acid at 20, 40 and 70 °C, respectively, while for 95% (v/v) aqueous ethanol the maximum migration ratios were 0.24%, 0.23% and 0.22% at 20, 40 and 70 °C.

An analytical method based on ICP-MS was developed for the determination of Ti in food simulants (3% (w/v) aqueous acetic acid and 50% (v/v) aqueous ethanol). The method was used to determine the migration of Ti from nano-TiO₂-PE films used for food packaging into food simulants under different temperature and migration time conditions. The maximum migration amounts into 3% (w/v) aqueous acetic acid were 1.4 ± 0.02, 6.3 ± 0.5 and 12.1 ± 0.2 μg kg(-1) at 25, 70 and 100°C, respectively, while into 50% (v/v) aqueous ethanol, the maximum migration amounts were 0.5 ± 0.1, 0.6 ± 0.03 and 2.1 ± 0.1 μg kg(-1) at 25, 70 and 100°C, respectively. Increasing the additive content in the film promoted migration of nanoparticles. The results indicated that the migration of nanoparticles might occur via dissolution from the surface and cut edges of the solid phase (film) into the liquid phase (food simulant).

A novel and simple method to detect isothiazolinone-type biocides (2-methyl-3-isothiazolinone (MI), 5-chloro-2-methyl-3-isothiazolinone (CMI), 1,2-benzisothiazolinone (BIT) and 2-octyl-3-isothiazolinone (OIT)) in paper used for food packaging by ultrasonic extraction coupled with UPLC-MS/MS was developed. Parameters affecting process efficiency such as extraction solvents, UPLC mobile phase, gradient elution procedure and MS/MS conditions were studied to optimise the operating conditions. Using the optimised gradient elution procedure, the retention time was less than 6 min. The limits of detection (LODs) were found to be between 0.001 and 0.010 mg kg⁻¹, which was validated using actual concentrations. After diluting the standard solution with a blank matrix, the linear calibration curve ranges were 0.002-1.000 mg kg⁻¹ for BIT and OIT, 0.005-1.000 mg kg⁻¹ for MI, and 0.020-1.000 mg kg⁻¹ for CMI, with correlation coefficients higher than 0.9985 (n = 6). A good level of precision with a mean recovery greater than 81.3% and a relative standard deviation (RSD) less than 6.2% were also obtained. A methodology has been proposed for the analysis of isothiazolinones in paper.

This study investigates the determination and migration of stabilizers and plasticizers from polyethylene terephthalate (PET). Two methods [ultrasonic extraction with dichloromethane or methanol and total dissolution with phenol/tetrachloroethane (m:m/1:1)] for pre-concentration of additives in PET material were performed. The diffusion of these additives from PET was evaluated by immersing in deionized water, acetic acid 3% (w/v), ethanol 20% (v/v), ethanol 50% (v/v) and isooctane at 20, 40, 55 and 70°C, respectively. The amount of additives in PET and food simulants was quantified by high-performance liquid chromatography-photodiode array detector (HPLC-PDA). The optimized HPLC method showed high correlation coefficients (R ≥ 0.9993), good precision, accuracy and reproducibility. Experimental diffusion coefficients (DP) were calculated according to a mathematical model based on Fick's second law, and the DP values of considered compounds ranged from 9.8 × 10(-15) to 1.4 × 10(-8) cm(2) s(-1) The experimental DP values were also compared with that predicted by currently used diffusion models. In addition, the effect of temperature on the diffusion rate was assessed. The effect of temperature on the diffusion coefficients followed an Arrhenius-type model with active energies ranged from 40.4 to 113.8 kJ mol(-1) for the target compounds.