Diffusive Gradients In Thin Films Based On Molecularly Imprinted Polymer For In-Situ Measurement Of Antibiotics In Wastewaters

Urban wastewaster is one of main output sources for antibiotics in the environment.Accuratre measurement of the concentrations of antibiotics in wastewaters is significant for estimating the total amount of antibiotics discharged into the environment through urban wastewater treatment systems,studying their environmental occurrence,fate,and environmental risks.Tranditional active sampling only provides the instant concentration of pollutants at the sampling time,and requires complex pretreatments prior to instrument analysis.Diffusive gradients in thin films?DGT?is an in situ passive sampling technique,which integrates sampling and pretreatment process and has ease operation and low cost.DGT can obtain the time-weighted-average concentration during the sampling time,achieving more representastive concentrations.In this study,we reported a novel DGT method based on molecularly imprinted polymer?MIP?for the determination of fluoroquinolones?FQs?and sulfonamides?SAs?antibiotics,and the method was successfully applied in in-situ measurement of antibiotics in urban wastewaters.Main research contents includ:FQs and SAs imprinted polymer?FQIP and SAIP?particles were synthesized by a precipitation polymerization method,respectively.The morphology and functional groups of FQIP and SAIP particles were characterized.Adsorption experiments showed that the maximum adsorption capacities of FQIP and SAIP to ofloxacin and sulfamethoxazole are 29.7mg/g and 88.52 mg/g,respectively.The adsorption process fitted well Langmuir adsorption isotherm.FAIP and SAIP showed specific binding ability towards FQs and SAs.A DGT method based on MIP binding gel was developed for determination of antibiotics in waters.MIP-DGT device consisted of a MIP inding gel,an agarose diffusion gel and a polyether sulfone membrane.The performance of MIP-DGT was investigated firstly in laboratory.Results showed that diffusion coefficients of 20 antibiotics?10 FQs and 10 SAs?at through the diffusion gel ranged from 2.19⁴.82×10^-6 cm²/s?25 ^oC?.90¹23%of recoveries for the antibiotics on the binding gel were obtained by using 2 mL of methanol/acetic acid?v:v=9:1?as eluent.The effective capacities of MIP-DGT for SAs and FQs were 47.4 and 34.6?g/gely.The uotake performance of MIP-DGT was relatively independent of solution pH?4.0⁹.0?,ionic strength?0.001⁰.75 M?and dissolved organic matter?DOM,0²0 mg/L?,and the accumulated masses of antibiotics on MIP-DGT showed excellent linear relationships with deployment time up to seven days.MIP-DGT coupled with LC-MS/MS was applied in the measurement of antibiotics concentration in one wastewater treatment plant?WWTP?in Dalian.Sulfamethoxazole,sulfapyridine,trimethoprim and ofloxacin were detected by MIP-DGT in the effluent for 3 days and 7 days deployment,and their concentrations ranged from 51 ng/L to 117 ng/L,with a total concentration of 306.5 ng/L,which was comparable to the concentration?473.6 ng/L?obtaioned by a active samplingmethod.The results confirmed that the develoeopd MIP-DGT was reliable for in situ measurement of the antibiotics in the wastewater.A new MIP-DGT method has been developed for in situ measurement of trace antibiotics in wastewaters,with high detection sensitivity and selectivity.The develoepod MIP-DGT provides an efficient tool for monitoring of trace antibiotics in complex environmental sampels.