An online liquid chromatography-gas chromatography-mass spectrometric(LC-GC-MS) method was developed for the detection of mineral oil components in recycled and virgin papers.Meanwhile

combined with multivariate statistical analysis

the differences between recycled and virgin papers were analyzed and identified.The mineral oil components in paper samples were extracted with n-hexane-ethanol(1∶1) solution

then analyzed by LC-GC-MS.The chromatograms were subjected to convolution and retention time alignment processing.Principal component analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA) were used to discriminate the recycled and virgin papers

and screen the differential components.Results showed that recycled and virgin papers could be clearly distinguished by multivariate statistical analysis.Compounds including diisopropyl naphthalene isomers

tetramethyl biphenyl isomers

dimethyl biphenyl isomers

isopropylbiphenyl isomers in mineral oil aromatic hydrocarbons(MOAH) fraction

and the compounds containing n-alkanes with carbon atom numbers from 25 to 33 in mineral oil saturated hydrocarbons(MOSH) fraction

were responsible for the chemical difference between recycled and virgin papers.