Study On The Determination Of Phenolic Endocrine Disruprors In Food By Covalent Organic Frameworks TpBD

Covalent organic frameworks(COF)is a pure organic porous material composed of organic construction primitive through reversible covalent bond.It has light quality and low density because it is made of pure organic elements C,N,B,O,etc.Most COF are 2-D or 3-D structures through specific continuous reaction of organic molecules monomer and have good crystallinity,ordered channel and large specific surface area.COF presents variety by different structural motifs and connection types and most of them has excellent thermal stability and chemical stability.Based on these advantages,the applications in gas storage,photoelectric,catalysis and other fields are peported.In this paper,a new application of COF is developed,which is used as solid phase extraction material combined with HPLC for the detection of trace phenol endocrine disruptor in food.A kind of spherical COF TpBD with superior stability was synthesized and characterized with SEM,TEM and N2 adsorption-desorption.This work evaluated the adsorption properties about TpBD on four target objects through adsorption kinetics and adsorption isothermal experiment,further determined the filling amounts into the SPE column.The factors affecting the recovery of targets were studied,such as the content of acetonitrile in the sample solvent,the pH of the sample solution,the sample flow rate,the type of eluent and the volume of the eluent.The reutilization performance of SPE column was evaluated.The optimal experimental conditions were selected through optimizing.The final content of acetonitrile is no more than 10%in the sample solvent.The optimal pH value is 4.The sample flow rate is 1.5 mL/min.We choose acetonitrile(10%acetic acid)as eluent and 4 mL as final elution volume.The TpBD-SPE column has been extracted continuously six times and still has a good recovery rate.This indicates that the column has good repeatability.Under the optimized conditions,each target got a wide linearity range at 0.5-100 ?g/L.The detection limits of BPF,BPA,OP,NP were 0.056,0.063,0.103,0.123?g/L respectively.The relative standard deviations(RSD)of these measurements were calculated to be 2.33%,2.82%,3.08%and 2.23%respectively after 9 parallel determinations at the test concentration of 10 ?g/L with 50 mL.The method established in this work was used to measure the four targets in beverages,carbonate beverages and milks.Recovery test of each target was operated with three different concentrations.The recovery rate of four targets was between 82.0%and 96.3%,indicating that TpBD-SPE has a good prospect in the enrichment and detection of trace phenol endocrine disruptor in food field.