Identification Of Recycled Paper And Sources Analysis Of Potassium Permanganate Consumption In Food Contact Paper

The food contact paper,paper waste recycling and recycled paper production,as well as the detection and migration of pollutants,the identification of recycled paper,and the potassium permanganate consumption of food contact paper,were reviewed.The content and main results of this research are as follows.Theonlineliquidchromatography-gaschromatography-mass spectrometry?LC-GC-MS?was used to detect mineral oil components in the paper samples.Combined with principal component analysis?PCA?and orthogonal partial least squares discrimination analysis?OPLS-DA?model,the differential compounds in recycled and virgin paper were analyzed and the classification between recycled and virgin paper was studied.The results showed that differential substances including dissopropylnaphthalene isomers,tetramethylbiphenyl isomers,dimethylbiphenyl isomers,isopropyl biphenyl isomers in MOAH fraction,n-paraffins?C25-C33?in MOSH fraction were responsible for the classification.Based on the differential compounds in mineral oil fraction,the PCA model succeeded in discriminating recycled and virgin paper.The headspace gas chromatography-mass spectrometry?HS-GC-MS?was used to analyze the volatile compounds in paper sample.Besides,PCA model was established for the classification of recycled and virgin paper.The results showed that a total of 46volatile substances were detected in 18 paper samples.The content of pentanal,hexanal,octanal,2-pentylfuran and tetramethylbiphenyl isomer in recycled paper was higher than that of virgin paper,which affected the distribution of recycled paper in the PCA score chart.These types of compounds can be part of the differential substances between recycled and virgin paper.Fourier transform infrared spectroscopy?FTIR?was used to detect paper sample.Based on the spectra in the region of 4000-600cm^-1and 1600-1200cm^-1,the PCA model was established to classify recycled and virgin paper.The results showed that the PCA model based on spectral data in the region of 1600-1200cm^-1achieved better separation these two kinds of paper.Potassium permanganate consumption?KMn O₄?of food contact paper and related raw materials?lignin,sugars?was analyzed,besides,the contents of total sugar and lignin in the water soaking solution of food contact paper were determined.Studies showed that the KMn O₄ consumption of most commercial papers in the study exceeded the limit of 40 mg/kg in GB4806.8.The contribution of KMn O₄consumption in most paper samples from lignin and total sugar in soaking solution was ranged from 42%to 94%,lignin and total sugar were two main sources of KMn O₄ consumption in food contact paper.