Portable Raman Spectroscopy for Screening of Phthalate Plasticizers in Food Contact Production Line Tubing and Bottle Cap Gaskets

Abstract

In this work, we evaluate two commercially available portable Raman spectrometers for their ability to accurately determine the presence of ortho-phthalate ester plasticizers, hereafter referred to as phthalates, in poly(vinyl chloride) (PVC) food contact production line tubing. Further, we aim to identify individual plasticizer compounds in the PVC tubing from a panel of multiple components with portable Raman spectroscopy. This is accomplished through library spectral matching of unknown tubing samples with on-instrument library Raman spectra. This library matching methodology functions via the comparison of Raman spectra between unknown food contact tubing samples and a panel of previously scanned, known tubing samples. In both known and unknown tubing, the samples are also analyzed via established gas chromatography-mass spectrometry (GC-MS) and direct analysis in real time-MS (DART-MS) methodologies to confirm the plasticizer identity and evaluate the accuracy of the Raman spectroscopic methods. In addition to food contact tubing, the developed methodology is applied to plasticizer analysis in bottle cap gaskets. Portable detection of phthalates in food contact materials is important, as it alleviates the need for high cost and timeconsuming laboratory-based testing while allowing for rapid, on-site detection of plasticizers. This work may provide information regarding the prevalence of various plasticizers currently used in food contact production line tubing and bottle cap gaskets. The results from the spectrometers investigated in this work show that the technologies hold potential as a valuable plasticizer screening tool for the food industry and regulators.