Application Of Supramolecular Solvents-based Extraction For The Determination Of Phthalate Esters And Their Metabolites

Phthalic acid esters?PAEs?are a class of chemical compounds that are widely used in plastic,building materials,clothing,personal care products,food packaging and medical products.They can enter into the environment during manufacture,use and disposal.Because of the large and widespread applications,PAEs have been widely detected in food,air,water,soil,and sediments.Due to their potential risks to human health,several PAEs including dimethylphthalate?DMP?,diethylphthalate?DEP?,butylbenzylphthalate?BBP?,dibutylphthalate?DBP?,bis?2-ethylhexyl?phthalate?DEHP?and dioctylphthalate?DOP?have been listed as Priority Toxic Pollutants by the United States Environmental Protection Agency?US EPA?,and different national and supranational organizations have established Specific Migration Limits?SMLs?or Tolerable Daily Intakes?TDIs?for several PAEs.Nevertheless,to the authors' knowledge,there is scarcely any standards and regulations specifically toward the the determination of PAEs and their metabolites in agricultural soil or sludge.Up to now,the researchers only reported one or several of PAEs in sludge samples,and all these extraction techniques,are extremely labor-intensive,time-consuming or need large volumes of toxic organic solvents,enhancing contamination risks.Therefore,it is of great significance to establish an effective method for the determination of PAEs in soil and sludge,which provides a theoretical basis for the assessment of the PAEs pollution.In this study,the suitability of alkanol-based supramolecular solvent liquid-liquid microextraction?SMS-LLME?coupled with liquid chromatography-diode array detector?HPLC-DAD?for the separation and preconcentration of six PAEs included in the US-EPA Priority Pollutants list and phthalate metabolites in agriculture soils,and meanwhile a method which based on supramolecular solvent purification and alkali hydrolysis was established for rapid determination of total PAEs in municipal sludge.The specific research content is divided into the following two parts:?1?For the first time,a new method for the simultaneous determination of 13 analytes with a wide range of polarity?from very polar compounds such as PA to highly lipophilic ones such as DnOP?in agricultural soils.The method based on the alkanol-based supramolecular solvent?SUPRAS?extraction,and the SUPRAS formation and extraction of analytes of the analytes are carried out simultaneously.The analytes were extracted within 15 minutes and don't require any purification steps.Besides simplicity and high effciency,low-cost,environment-friendly,the system setup was implemented using conventional laboratory equipment.Several conditions affecting extraction effciency such as the concentration of major components of the nanostructured supramolecular assembly?tetrahydrofuran and alkanol?,alkanol type,solvent pH,and solvent ionic strength were investigated and optimized as well.The analytical method was validated under the optimal selected conditions.As a result,the calibration plot of 13 analytes ware found to be linear in the range of 0.25¹0 ?g mL-1,with correlation coefficients?r?greater than 0.9917;the detection limit and the quantification limit were 0.2¹.9 ?g g^-1 and 0.6⁶.5 ?g g^-1.The recoveries obtained were in the range of 75¹06%,with relative standard deviations?RSDs?lower than 4.8%.Finally,the validated method was applied to thirty-two agriculture soil real samples.?2?A very simple,fast and environmentally friendly sample extraction method was proposed for the analysis of total PAEs in municipal sludge by using supramolecular solvent purification-alkaline hydrolysis combined with low toxic tributyl phosphate extraction.The PAEs were convert into phthalic acid?PA?with high polity and analyzed by HPLC-DAD.After parameters affecting the hydrolysis efficiency of PAEs were examined,the method was validated under the optimal selected conditions.The linear range of phthalic acid was 0.5⁵0 ?g mL-1,with a correlation coefficients greater than 0.9999.The LOD and LOQ were 13.31 and 44.03 nmol g^-1,respectively.The recoveries of target analyte in the three levels of spiked samples were in the range of 88⁹4%.The repeatabilities,expressed as RSDs,were 3.8% for intra-day and 5.6% for inter-day.The total PAEs contents of seven municipal sludge samples were found in the range of 0.39⁰.63 ?mol g^-1.