Preparation Of A New Hybrid Monolithic Column And Its Application In The Detection Of Polycyclic Aromatic Hydrocarbons

Polycyclic aromatic hydrocarbons?PAHs?are widely existing peisistant organic pollutants,which can be detected in air,water and soil.Some of the PAHs were confirmed as carcinogens.So,PAHs were listed as priority environmental control pollutants and monitored by China,EPA,the European Union,and many other countries/organizations.Due to the complex matrix of environmental samples and low concentration of PAHs,it was difficult to be analyzed directly by conventional instruments such as gas chromatography?GC?or high performance liquid chromatography?HPLC?.Therefore,an efficient sample preparation was curcial to concentrate the PAHs selectively and clean up the interferences prior to the instrumental analysis.Many pretreatment methods for PAHs have been reported in past decades,including liquid-liquid extraction,solid-phase extraction and solid-phase microextraction?SPME?.In recent years,SPME has gained extensive attention because of its advantages of less sample amount,no?less?extraction solvent,simple operation,and high sensitivity.Among the reported methods,in-tube solid-phase microextraction was widely applied for its easy in material preparation and coupling to analytical instruments.In this work,novel hybrid capillary monolithic columns were prepared and applied for the sample preparation of PAHs.By coupling the in-tube SPME with GC,a sensitive and reliable method was achieved for the analysis of PAHs in environmental samples.Firstly,a novel POSS-AMH hybrid monolith was prepared using monomers of PSS-methacryloyl substituted cage mixture,n=8,10,12?POSS-MA?and 2-aminoethyl methacrylate?AMH?through free radical polymerization.In improve the hydrophobic interaction,the capillary monolithic column was modified by three hydrophobic monomers of octadecyl isocyanate,octyl isocyanate and p-tolyl isocyanate,respectively,based on the rapid reaction of the functional group isocyanate?-NCO?and amino?-NH₂?.The prepared columns were systematically evaluated,and it was found,all columns showed good mechanical stability.Alao typical hydrophobic retention was skilled in the separation of hydrophobic substances with high column efficiency?up to 82300 N/m?of the monolithic column.After modification,both the hydrophobic retention and the column efficiency were improved,and the column efficiency up to 96000 N/m was achieved for these columns.Next,the prepared hybrid monolith was used as a solid-phase microextraction collumn to selectively concentrate the PAHs from complex samples.Under the optimal SPME conditions,a new analytical method combining SPME with GC was evaluated.In the range of0.01-50?g/L,good linear relationships were achieved for the tested 16 PAHs with correlation coefficients over 0.99.The detection limits and quantification limits of the method were0.46⁷0.19 ng/L and 1.53²33.97 ng/L,respectively.Meanwhile,excellent recoveries of the SPME from 84.4%to 104.2%were found and the enrichment factor of 300.The intra-day and inter-day reproducibities in term of relative standard diviation?RSD?were 1.8%¹1.7%and1.9%¹0.4%?n=6?,respectively,suggesting the robustness of the analytical method.Finally,the developed analytical method was applied in the analysis of PAHs in the ice samples taken from the estuary of the Liao River.The experiments showed that naphthalen,acenaphthene,acenaphthylene,fluorine,phenanthrene,anthracene,fluoranthene and pyrene were detected at eight sampling sites,with the concentrations of ND¹38.42 ng/L.In a word,the Liao River was contaminated with the PAHs.These results also confirmed that the SMPE-GC method could be applied in the analysis of PAHs in complex environmental samples.