Determination of polyadipates migrating from lid gaskets of glass jars. Hydrolysis to adipic acid and measurement by LC-MS/MS

Multiresidual LC-MS analysis of plasticizers used in PVC gaskets of lids and assessment of their migration into food sauces

Plasticizers may migrate from polyvinyl chloride (PVC) gaskets into the foodstuffs mainly by direct contact during the packaging and sterilization procedure, but also by means of occasional contacts occurring during shipment and storage. The present work reports a reliable liquid chromatography-mass spectrometry (LC-MS) method able to quantify the main plasticizers used in the PVC closure gaskets for metal lids to verify their compliance in both food contact materials and foodstuffs. The atmospheric pressure chemical ionization in the positive ion mode resulted the best performing interface for the multiresidual detection of the plasticizers taken into account, followed by selected/multiple reaction monitoring, selected ion monitoring or full scan experiments, depending on the compounds to detect. The method was single-laboratory validated, demonstrating to reach a good sensitivity, thus making possible to perform analysis without any preliminary sample purification or concentration step. It proved to be effectively applicable not only for the determination of plasticizers in PVC gaskets but also in complex food matrices. In particular, it was applied for monitoring plasticizer migration into sauces placed in contact with the lids in worst storage conditions, observing therefore their trend during the shelf-life. Copyright © 2016 John Wiley & Sons, Ltd.

Use of atmospheric pressure solids analysis probe time-of-flight mass spectrometry to screen for plasticisers in gaskets used in contact with foods

RATIONALE

Plasticisers are used in the PVC gaskets of metal closures on glass jars and bottles used for foods and beverages. They may migrate and so contaminate the packed foodstuff. The plasticisers are present in a high proportion and are often a complex mixture of substances leading to time-consuming analytical methodologies. This work describes a rapid screening method to identify the plasticisers used.

METHODS

Analysis was carried out by direct sampling of the gaskets using atmospheric pressure solids analysis probe (ASAP) with time-of-flight (TOF) mass spectrometry (MS) using a SYNAPT G2 HDMS system. The accurate mass information collected was then compared to a user-prepared database of plasticisers to aid identification.

RESULTS

The rapid identification approach was shown to be successful for 24 gasket samples previously analysed by alternative more lengthy gas chromatographic (GC) methods. Quantification by dissolution followed by standard addition was also demonstrated to be reliable.

CONCLUSIONS

The ASAP-TOFMS method is a useful technique for rapidly screening gaskets for the presence of plasticisers. It can be used to identify specific gaskets deserving of further quantitative analysis by chromatographic methods, saving time and money by avoiding unnecessary analyses. Copyright © 2015 John Wiley & Sons, Ltd.