Rapid Screening of Polycyclic Aromatic Hydrocarbons in Food Contact Materials by Surface-enhanced Raman Spectroscopy Combined with Principal Component Analysis

KeyWord:surface-enhanced Raman spectroscopy  principal component analysis  food contact materials  polycyclic aromatic hydrocarbons  rapid screening

Abstract:

      Analysis of polycyclic aromatic hydrocarbons£¨PAHs£© has drawn great attention due to their high bio-accumulative£¬carcinogenic and teratogenic properties£®PAHs might migrate to foods through contaminated food contact materials£¨FCMs£©£¬causing huge potential damages to human health£®It is very important to screen PAHs in FCMs with high rapidity and accuracy£®Surface-enhanced Raman spectroscopy£¨SERS£© is a promising optical tool for contaminants screening due to its unique properties of rapidity£¬sensitivity and molecule fingerprint characteristic£®However£¬PAHs is a class of pollutants including over 200 chemicals with two or more benzene rings£¬meaning the similar structure and overlapping of characteristic Raman peaks£®Principal component analysis£¨PCA£© is an ideal data processing method£¬which could be used to extract useful information from large amount of data by dimensionality reduction process.Researchers have developed methods for identifying chemicals with similar structure by SERS combined with PCA method£¬obtaining good segregation and identification results£®In this paper£¬a simple analytical method was established for rapid screening of four PAHs£¬i.e.pyrene£¨Pyr£©£¬fluoranthene£¨FlA£©£¬benzo£Ûb£Ýfluorathene£¨BbF£© and benzo£Ûk£Ýfluorathene£¨BkF£© in FCMs of polyethylene terephthalate£¨PET£© and polypropylene£¨PP£© based on the combination of SERS and PCA£®Ag nanoparticles£¨AgNPs£© were mixed with inorganic salt of potassium iodide£¨KI£© to form the aggregated AgNPs with denser¡°hot spot¡±£¬which were used as the enhanced substrate for SERS analysis with high sensitivity£®In order to obtain the optimum sensitivity£¬some analytical parameters including inorganic salt£¬concentration of KI£¬incubation time and volume ratio of KI¡ÃBbF¡ÃAgNPs were optimized£®Under the optimum conditions£¬the Raman characteristic peak of Pyr£¬FlA£¬BbF and BkF were recorded and sorted for next PCA analysis£®Afterwards£¬PCA method was adopted for the rapid identification of four PAHs to overcome the overlapping of characteristic peaks with similar structure£®Results showed that the four PAHs could be easily and obviously identified in the same or different concentration or mixed samples£®In addition£¬the minimum tolerance method was used for identifying PAHs in mixed samples with better segregation and identification results£¬indicating that the minimum tolerance method could eliminate interference of mixed PAHs samples with similar structure£®Furthermore£¬two FCMs including PET and PP were migrated in 95%£¨by volume£© ethanol at 100 ¡æ for 4 h to evaluate the feasibility and accuracy£®The migration of PAHs in PET and PP FCMs were rapidly screened and identified based on the established method with satisfactory results£¬indicating the practicability and accuracy of the PCA£­SERS method£®The developed method shows great potentials in rapid screening of four PAHs in FCMs migration with high rapidity£¬accuracy and practicability£¬which could be used to monitor the safety of FCMs containing PAHs£®Also£¬the method could be used for the detection and screening of other contaminants in FCMs£®