| Because of the properties of lightweight, user-friendly, easy processing, cheap and other advantages, plastic materials are used in the field of food and drug packaging extensively. The quality of plastic packaging materials, which will influence human health, safety and life,should be responsible for the quality and safety of food and medical products. Hence, during the work for quanlity control of food and medical products, the packaging materials should also be tested to ensure the absence of hazardous leachables. Mass spectrometry (MS), liquid chromatography-mass spectrometry (LC-MS) and supercritical fluid chromatography-mass spectrometry (SFC-MS) are effective technologies in identification and determination of various compounds, due to the high sensitivity, high resolution, strong specificity and efficient sparation ability of the techniques. This paper did the following researches by using MS, LC-MS and SFC-MS for quality control and safety assessment of plastic packaging materials of food and medical products:(1) In order to meet the demand of fast identification of polymer additives, an ESI-QqQ MS library for 100 additives was built. Utilizing direct injection acquisition mode, we obtained the MS and MS/MS spectra of each of the additives. According to the MS/MS results, the dissociation mechanisms of the additives were deduced. In the end, an ESI-QqQ MS library containing the information of name, formula, MS and MS/MS spectra and the corresponding dissociation mechanisms for 100 polymer additives, was established. To test the application ability of the library, a set of eight polymer additives were spiked in blank polypropylene powder and made a simulant plastic sample. The eight additives include Tinuvin 328, Tinuvin 770, Cyasorb 2908, Cyasorb 3853,Irgafos 168, Antioxidant 405, Irganox 565, Irganox MD 1024. The sample was then analyzed by accelerated solvent extraction-electrospray ionization-triple quadrupole mass spectrometry (ASE-ESI-MS/MS).Using molecular weight search in the library, and comparing the MS/MS spectra, eight additives in the plastic sample could be easily identified.Moreover, the additives were quantified by ESI-MS/MS without column separation. Limits of detection (LOD) for the multi-reaction-monitoring(MRM) mode of the ESI-MS/MS analysis varied from 0.1 to 10 ?g·L-1.The relative recoveries ranged from 84.0% to 120%. The method was applied to the analysis of a real polypropylene sample, and three additives were determined including Irgafos 168?Cyasorb 3853 and Cyasorb 2908 with contents of 0.182%?0.108% and 0.077%, respectively. The method was confirmed by UPLC-MS/MS and the results were in excellent accordance.(2) An atmospheric solid analysis probe (ASAP) combined with quadrupole time-of-flight mass spectrometry (QTOF MS) method was used to build an ASAP-QTOF MS library for 100 polymer additives. By this method, sample pretreatment could be eliminated. The tip of glass tube of the ASAP was dipped into the sample and subsequently analyzed by QTOF MS. For acquiring good spectra, some crucial parameters, such as desolvation gas temperature, corona current, sample cone voltage and collision energy, were optimized. In the end, an ASAP-QTOF MS library containing the information of name, formula, MS and MS/MS spectra,exact mass and the corresponding dissociation mechanisms for 100 polymer additives were established. To verify the application of the MS library, the ASAP-QTOF MS method was applied to identify complex additives, a simulated PP sample and a real polymethylmethacrylate(PMMA) sample purchased from local market. By searching the exact mass, and comparing the MS and MS/MS spectra of samples with standards in the library, complex additives such as Irganox GX 2921, as well as additives in PP and PMMA samples, could be identified quickly and easily. The high-resolution ability of QTOF MS increased the confidence of peak identification as well. Moreover, the results also provided the character information of PP polymer matrix with mass differences of 42 Da (the mass of the repeat unit of PP) between adjacent peaks, and PMMA polymer matrix with mass difference of 100 Da between adjacentpeaks.(3) The methods developed above were mainly used in the rapid identification of polymer additives in plastic materials. However, when food and drugs directly touch the plastic packaging materials, additives and low molecular weight compounds would migrate to food and drugs,thus result contaminations. The contents of the migrants are usually at trace-levels in the complex matrixes of the food and drugs. Hence, to improve the sensitivity of the method and determine the migrants accurantly, MS library was extended and a library containing 174 polymer additives with the information of their names, structures,retention times, MSE and MS/MS spectra, fragments and classifications was established by ultra-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UPLC-QTOF MS). First of all, the reliability of the construction process of the library was guaranteed by system stability and suitability test. By systematically optimizing the chromatography and mass spectrometry conditions, all of the additives could be eluted under the same gradient with good response in mass spectrometry. Importing the information of additives to UNIFI software,an on-line searching library could be obtained. For the better use of the library, identification parameters, such as mass error, retention times,fragments and isotope pattern, were evaluated. This method was successfully applied to the analysis of migrants from plastic packaging materials in real vaccine, and the polymer additives in vaccine were identified and quantified quickly. In addition, unknown compounds,which could not be identified by automatically searching the library,could be elucidated by 'Elemental composition','ChemSpider Search'and 'Mass fragment match' tools. This protocol could save the effort on the identification of unknown compounds. In the end, Irgafos 168,Irganox 1076, Irganox 1010, Irganox 3114 FF, DBP, ODP, DIDP and 2-hydroxy-1,3-cyclohexanedicarboxylate in the vaccine were identified with the concentration in the ranges of 0.85 to 21.91 ?g·L-1.(4) The migration behaviors of 13 Pls from polyethylene (PE)packaging to 5 food simulants according to regulation EU No. 10/2011 were studied by ultra-high performance supercritical fluid chromatography combined with photodiode array detector and tandem mass spectrometry (UPSFC-PDA-MS/MS). The method simultaneously analyzed 13 PIs within 4.5 min with low limits of detection of 0.02-2.16?g·L-1, which could meet high throughput analysis for control the quality of food packaging. According to the results, the general rule of the migration of PIs is, the lower the temperature, the stronger the hydrophilic simulation, the more complex molecules, the smaller the migration rate. In 50% ethanol (simulant D1) at 40?, the total migration of PIs is the highest. Irgacure 819, TPO and Darocure 1173 have the lowest migration rates among all 13 PIs, and Irgacure 907 has the highest migration rate, which suggests that Irgacure 819, Darocure 1173 and TPO should be preferably selected by plastic food packaging manufacture for food safety. |
PDF Full Text Request