[Rapid analysis of the specific migration of seven terephthalates and benzoates from plastic food contact material and products by high performance liquid chromatography-ultraviolet detection].

A method based on high-performance liquid chromatography-ultraviolet (HPLC-UV) detection was developed for the rapid analysis of the specific migration of seven terephthalates and benzoates (TPBAs) in seven food simulants (10% (v/v) ethanol, 3% (m/v, i. e. 3 g/100 mL) acetic acid, 4% (v/v) acetic acid, 20% (v/v) ethanol, 50% (v/v) ethanol, 95% (v/v) ethanol, or olive oil)). Detailed comparisons were made on the extraction or purification of the seven TPBAs in olive oil food simulants by solvents, QuEChERS dSPE EMR-Lipid technology, and Captiva EMR-Lipid technology. The seven TPBAs were separated completely within 17 min by gradient elution on a phenyl column using water and methanol as the mobile phase. The detection wavelength was set at 237 nm. The injection volume was 10 µL. The linearities of the seven TPBAs were good, with r≥0.9998 at 1-80 mg/L or 8-160 mg/kg in the seven food simulants. The average recoveries of the seven TPBAs were between 91.7% and 106%, with relative standard deviations (RSDs) between 0.1% and 3.1% (n=6). The limits of quantification were 0.2-8.1 mg/kg. This method is simple, with convenient pretreatments, good chromatographic separation and linear relationships, as well as satisfactory recoveries and RSDs. The method has been applied to detect the specific migration of the seven TPBAs in real samples.

Determination of methacrylic acid in food simulants by pyrolytic butylation-gas chromatography.

An on-line pyrolytic butylation approach was proposed to determine methacrylic acid (MA) in food simulants by gas chromatography (GC) without an expensive pyrolyzer. MA in food simulants was converted into butyl methacrylate in the presence of tetrabutylammonium hydroxide (TBAH) without any pretreatment at 330°C in the injection-port, contributing to high GC signal response. The derivatizing conditions for the proposed method were optimized, namely the injection-port temperature, type and amount of the organic alkaline used for derivatization. A series of standard solutions of MA in the range of 1.0-50mg/kg were analyzed with correlation coefficient r≥0.9975. The limits of detection (LODs) were less than 0.15mg/kg for MA in four matrix simulants (distilled water, 3%w/v acetic acid, 10%v/v ethanol, and isooctane). Relative standard deviations (RSDs) for retention time, peak height and peak area were all less than 3.88%. The technique was successfully applied to the analysis of MA migrating from plastic cup samples, with recoveries of added MA in the range of 96.5-123.0%. Direct injection of the simulants into the GC system after migration tests, without any pretreatment step, makes the developed method of great value for rapid screening analysis of samples in bulks.

High-performance liquid chromatography - Ultraviolet method for the determination of total specific migration of nine ultraviolet absorbers in food simulants based on 1,1,3,3-Tetramethylguanidine and organic phase anion exchange solid phase extraction to remove glyceride.

The glyceride in oil food simulant usually causes serious interferences to target analytes and leads to failure of the normal function of the RP-HPLC column. In this work, a convenient HPLC-UV method for the determination of the total specific migration of nine ultraviolet (UV) absorbers in food simulants was developed based on 1,1,3,3-tetramethylguanidine (TMG) and organic phase anion exchange (OPAE) SPE to efficiently remove glyceride in olive oil simulant. In contrast to the normal ion exchange carried out in an aqueous solution or aqueous phase environment, the OPAE SPE was performed in the organic phase environments, and the time-consuming and challenging extraction of the nine UV absorbers from vegetable oil with aqueous solution could be readily omitted. The method was proved to have good linearity (r≥0.99992), precision (intra-day RSD≤3.3%), and accuracy(91.0%≤recoveries≤107%); furthermore, the lower limit of quantifications (0.05-0.2mg/kg) in five types of food simulants(10% ethanol, 3% acetic acid, 20% ethanol, 50% ethanol and olive oil) was observed. The method was found to be well suited for quantitative determination of the total specific migration of the nine UV absorbers both in aqueous and vegetable oil simulant according to Commission Regulation (EU) No. 10/2011. Migration levels of the nine UV absorbers were determined in 31 plastic samples, and UV-24, UV-531, HHBP and UV-326 were frequently detected, especially in olive oil simulant for UV-326 in PE samples. In addition, the OPAE SPE procedure was also been applied to efficiently enrich or purify seven antioxidants in olive oil simulant. Results indicate that this procedure will have more extensive applications in the enriching or purification of the extremely weak acidic compounds with phenol hydroxyl group that are relatively stable in TMG n-hexane solution and that can be barely extracted from vegetable oil.

[Simultaneous determination of total specific migration limit of seven benzene polycarbonic acids and their derivatives in food simulants by high performance liquid chromatography-ultraviolet detection].

A novel method for simultaneous determination of total specific migration limits (SML (T)) of trimellitic, isophthalic, terephthalic, phthalic acid and their derivatives (1, 2, 4-benzenetricarboxylic anhydride, isophthaloyl chloride and terephthaloyl chloride) in food simulants (10% (v/v) ethanol, 20% (v/v) ethanol, 50% (v/v) ethanol, 3% (w/v) acetic acid and olive oil) was developed by high performance liquid chromatography-ultraviolet detection (HPLC-UV). After the migration test, the soaking solution was cooled down and vortexed. After the extraction of olive oil food simulants with 0. 1% (w/v) ammonium acetate aqueous solution, the clear aqueous solution or other aqueous food simulants was filtered through a hydrophilic polytetrafluoroethylene filter with a disposable syringe before injection. The Synergi Polar-RP column (250 mm x 4.6 mm, 4 µm) and gradient elution mode were selected. The variable wavelength detector was set at 232 nm. The limits of quantification were 0.1-0.2 mg/kg; the linearity of the method was good with r2 > 0.999 91 over the range from 0.5 to 12 mg/L for aqueous food simulants or 0.5 to 12 mg/kg for olive oil food simulants. The recoveries of them were between 94. 3% and 105% with the relative standard deviations between 0.1% and 2.3% at the levels of 1.25, 2.50, 6.25 mg/kg. The method shows the low limits of detection, good recoveries and accuracies, and meets the requirement of ( EU) No 10/2011 regulation for the total specific migration limits of trimellitic, isophthalic, terephthalic, phthalic acids and their derivatives. The method has been applied to the analysis of food contact material samples.

[Rapid analysis of 28 primary aromatic amines in aqueous food simulants by high performance liquid chromatography-tandem mass spectrometry].

A novel method for rapid analysis of the migration amounts of 28 primary aromatic amines (PAAs) in aqueous food simulants (10% ethanol, 30 g/L acetic acid and 20% ethanol aqueous solution) was developed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After the migration test, the soaking solution was cooled down from 100 degrees C, vortexed, filtered through a hydrophilic polytetrafluoroethylene filter with a disposable syringe, and then the filtrate was analyzed by HPLC-MS/MS. A Zorbax SB-Phenyl column (250 mm x 4.6 mm, 5 microm) was selected for chromatography. The mobile phase consisted of water and 0.1% formic acid-25% acetonitrile-methanol solution with gradient elution. The 28 PAAs in aqueous food simulants were detected by tandem mass spectrometer operated in positive electrospray ionization (ESI+) and multiple reaction monitoring (MRM) mode. The limits of quantification for the 28 PAAs were between 0.002 microg/L and 10 microg/L. The linearity of the method was good with correlation coefficients (r2) greater than 0.995 over the concentration range from 5 microg/L or 10 microg/L to 100 microg/L. The average recoveries of the 28 PAAs were between 76.6% and 114% with the relative standard deviations between 1.53% and 8.97% at the levels of 10, 20, and 40 microg/L. The method shows rapid pretreatment, the lower limits of quantification, good recoveries and accuracies, and meets the requirement of European Union (EU) No 10/2011 regulation for the specific migration of PAAs. The method has been applied to analyze the 28 PAAs in different aqueous food simulants from the migration test of 30 batches of food contact material samples exported to EU.