| The mass production and widespread use of drugs have put forward new requirements for environmental and health research in public health.Determining the concentration of drugs in samples of the general population is critical in drug monitoring,drug abuse screening,disease preventing and other fields.Urine sample is a common biological sample in environment and health research of public health.However,due to its characteristics of complex matrix,low drug concentration to be analyzed,and small amount of collection,proper pretreatment and use of urine samples are the basic premises to give full play to its value in environmental and health research.As a new microextraction technology,flat membrane liquid phase microextraction(FM-LPME)has been widely used in sample pretreatment because of its high extraction efficiency and strong ability of anti-matrix interference.The typical FM-LPME device is composed of donor phase,acceptor phase,and supported liquid membrane(SLM).In general,the SLM is formed by filling the pores of the polymer membrane with small molecule organic solvent.Different organic solvents have different affinities with analytes,so as to achieve different extraction effects.However,the existing small molecule organic solvents can only extract acidic analytes or basic analytes,and can't meet the high-efficiency extraction of both acidic and basic analytes at the same time.This separation characteristic of organic solvents limits the application of FM-LPME in the field of environmental and health research(In environment and health research,it is necessary to analyze a variety of drugs with different properties in urine samples).Constrained by the lack of versatility of existing organic solvents,extraction of multiple types of drugs with FM-LPME requires a variety of organic solvents.This extraction method will consume valuable sample resources in public health research.Therefore,the development of the FM-LPME that has good extraction effects on both acidic and basic analytes to acheive the simultaneous separation of analytes of different properties in a small number of biological samples is a difficult problem in the field of health inspection and quarantine.Recent research in our laboratory showed polypropylene glycol with a molecular weight of 4000(PPG4000)has a good affinity with acidic analytes and basic analytes and is a potential organic solvent with versatility applicability to analytes of different properties.In this study,PPG4000 was used as an organic solvent to explore its extraction performance for acidic and basic analytes in the FM-LPME.Besides,according to the characteristics of the variety of drugs to be tested in the urine samples and the small amount of sample collection,to give full play to the value of the sample,this study intended to use the FM-LPME system based on PPG4000 as the organic solvent to continuously extract and enrich the acidic and basic drugs in the same sample,and further apply this method to the extraction and analysis of two types of drugs in urine samples.Although the continuous extraction of acidic/basic drugs saves the amount of sample consumed,the process takes a long time.In order to solve this shortcoming,researchers developed electric field-assisted liquid-phase microextraction,also known as electromembrane extraction(EME).The basic principle of EME is that the analytes in the donor phase quickly pass through the SLM and enter the acceptor phase depending on the driving force of the electric field.According to the extraction principles of the two sample pretreatment technologies,the FM-LPME extraction system requires the analytes to be neutral and charged in the donor phase and the acceptor phase,respectively,and the analytes in EME exist as a charged ion state in both the donor phase and the acceptor phase.In the acidic donor phase,the acidic analytes are in the molecular state and the basic analytes are in the ionic state.Theoretically,the combination of LPME and EME(LPME-EME)can simultaneously extract acidic/basic analytes from a donor phase at the same p H value.Therefore,this reaserch intended to combine use of LPME and EME so that achieve simultaneous extraction of target drugs of different properties in the same sample,further reducing the amount samples used in public health reaserch and shortening the time of sample pretreatment in health inspection and quarantine.Part 1 Research on liquid-phase microextraction based on polypropylene glycol supported liquid membraneObjective:Flat membrane liquid phase microextraction(FM-LPME)has become an efficient sample pretreatment technology because of its strong ability of anti-matrix interference and high extraction recovery.However,the existing small molecular organic solvents are limited in environment and health research because they don't have a good affinity with both acidic and basic analytes at the same time.In order to overcome the lack of versatility of the traditional organic solvents,PPG4000 was used as an organic solvent to explore its extraction performance for acidic and basic analytes in the FM-LPME.Demonstrating that PPG4000 is a new organic solvent with versatility applicability in the FM-LPME.Methods:PPG4000-SLM was prepared by ultrasonic synthesis method with PPG4000.Naproxen(NAP),flurbiprofen(FLB)and diclofenac sodium(DIC)were used as acidic model analytes,while haloperidol(HAL),fluoxetine(FLU)and sertraline(SER)were used as basic drugs to explore versatility of the FM-LPME based on PPG4000-SLM.The optimum extraction condition was obtained by the optimization of extraction temperature,donor phase,acceptor phase and extraction time on the extraction recoveries of acidic and basic analytes.Then,the extraction performance of the FM-LPME based on PPG4000-SLM was evaluated by the extraction recoveries of the analytes under the optimum extraction conditions.The binding force of PPG4000 with polypropylene(PP)membrane was clarified by the reusebility of PPG4000-SLM.Results:Under the optimum extraction conditions,the recoveries of acidic drugs(NAP,FLB and DIC)in water samples by FM-LPME based on PPG4000-SLM were97.14±3.20%,99.17±1.52%and 92.13±1.19%,respectively.Meanwhile,the recoveries of acidic drugs in a urine sample were 93.11±1.14%,95.16±0.88%and 95.85±0.97%,respectively.The recoveries of HAL,FLU and SER in a water samples were102.31±2.55%,89.27±1.15%and 70.48±2.49%respectively,while the recoveries of the basic analytes in a urine sample were 99.06±3.47%,88.20±3.16%and 63.48±1.49%,respectively.The extraction performance using PPG4000 as the a SLM solvent for acidic and basic analytes in water samples and urine samples was consistent with that of the traditional SLM solvents.PPG4000-SLM can extract at least 12 times without affecting the extraction performance of FM-LPME on the analytes.Conclusions:The FM-LPME based on PPG4000-SLM has a good extraction effect for acidic analytes and basic analytes,and its extraction performance is consistent with the respective optimal organic solvents for acidic analytes and basic analytes.The reusebility of PPG4000-SLM indicated that PPG4000 had a strong binding force with the PP membrane.Therefore,PPG4000 was a new SLM solvent with excellent recoveries for both acidic and basic analytes.Part 2 Continuous extraction of acidic and basic drugs by liquid-phase microextraction based on polypropylene glycol supported liquid membraneObjective:In environment and health research,it is necessary to analyze both acidic drugs and basic drugs in urine samples.Due to lack of versatility of existing membrane solvents,extraction of multiple types of drugs requires a variety of organic solvents.This extraction method will consume valuable sample resources in public health research.Combining the characteristics of the variety of drugs in the urine samples and the small amount of sample collection,the continuous extraction of drugs with multiple properties in the same sample is particularly important for giving full play to the value of the samples.Based on the work of part 1,this part intended to continuously extract acidic/basic drugs in urine samples by adjusting the composition of the donor phase and the acceptor phase to achieve the extraction and separation of acidic and basic drugs in the same sample.Methods:Through the characterization of PPG4000-SLM before and after extraction,the stability of PPG4000 in the extraction was evaluated.Different extraction sequences were used to analyze the extraction recoveries of drugs in each phase,and the feasibility of continuous extraction of acidic and basic drugs was clarified in water samples by the FM-LPME based on PPG4000-SLM.Furthermore,the potential of continuous extraction of acidic and basic drugs in urine samples was explored by adjusting the different concentration ratios between these two types of drugs.The optimal conditions for continuous extraction of acidic and basic drugs in urine were studied by selecting different extraction sequences and the concentration of sodium hydroxide(Na OH)solution at extraction intervals.Under the optimal condition,the liquid chromatography-tandem mass spectrometry(LC-MS/MS)was used to verify the performance of continuous extraction for the acidic and basic drugs in urine samples.Results:In the study of the stability of PPG4000-SLM,the PPG4000-SLM before and after phase I of extraction was characterized.There was no obvious change in the water drop contact angle of PPG4000-SLM before and after the phase I of extraction.Scanning electron microscope(SEM)results showed that PPG4000 was still filled in the PP membrane after the end of the first phase extraction.there was almost no loss of PPG4000 after the end of the first stage extraction by FT-IR spectrum.For extracting acidic drugs and then basic drugs,the recoveries of NAP,FLB,DIC,HAL,FLU and SER were 94.14±2.92%,92.27±2.32%,91.35±3.12%,99.35±6.24%,95.24±5.07%and69.55±1.49%,respectively.Then the extraction sequence was reversed,and the recoveries of the six drugs were 94.23±2.15%,92.85±2.49%,90.16±2.87%,98.32±6.78%,92.70±2.72%and 62.50±2.99%,respectively.During continuous extraction in urine,when the concentration of 20 mol L-1(1?L)Na OH solution was added at the extraction interval,the recoveries of drugs were the highest(94.51±7.51%,86.18±7.70%,90.96±1.02%,91.69±1.89%,80.16±1.84%and 61.60±0.67%for NAP,FLB,DIC,HAL,FLU,and SER,respectively.).Finally,the performance of continuous extraction was evaluated by LC-MS/MS for the acidic and basic drugs in urine.The results showed that the linearity range of NAP,FLB was 10?2000 ng m L-1 and the linearity range of DIC was 1?2000 ng m L-1,the correlation coefficients(R2)of the acidic drugs were higher than 0.99,the limits of detection(LOD)was 0.14?0.42 ng m L-1,and the limits of quantification(LOQ)was 0.50?1.38 ng m L-1.The linear range of the basic drugs ranged from 10 ng m L-1 to 2000 ng m L-1,with R2>0.99,LOD was 0.64 ng m L-1?0.98 ng m L-1 and LOQ of drugs was 2.12 ng m L-1?3.26 ng m L-1.The precision of all of the drugs was less than 9%.Conclusions:The characterization of PPG4000-SLM showed that PPG4000 had almost no loss after phase I of extraction,indicated that PPG4000-SLM was stable in the FM-LPME.In the continuous extraction of acidic/basic drugs from water samples and urine samples,the distribution and recoveries of the drugs were not affected by the extraction sequence,which indicated that the extraction of the two kinds of drugs was two independent processes.The good extraction performance for the proposed method showed that the continuous FM-LPME of acidic and basic drugs was a reliable sample pretreatment technique based on PPG4000-SLM in urine samples.Part 3 Simultaneous extraction of acidic drugs and basic drugs by combination of liquid-phase microextraction and electromembrane extractionObjective:The sample pretreatment process occupies more than half the time of sample analysis in health inspection and quarantine.Convenience and rapidity have become another development trend of sample pretreatment technology.The basic principle of EME(Electromembrane extraction)is that the analytes in the donor phase quickly pass through the SLM and enter the acceptor phase depending on the driving force of the electric field.The optimal recovery of analytes can be obtained in a short time.Based on the results in the previous two parts,this chapter intended to use the combination of LPME and EME(LPME-EME)to extract the acidic/basic drugs in the sample at the same time,to achieve rapid extraction and separation of acidic/basic drugs in the same sample.Methods:The interaction between LPME and EME was clarified by LPME alone,EME alone,LPME-EME using PPG4000 as organic solvent.Furthermore,through the optimization of experimental conditions(including the composition of donor phase and extraction time),and the optimum extraction conditions were obtained.The feasibility of LPME-EME in urine samples was explored by adjusting the different concentration ratios between these two types of drugs.Furthermore,optimized the optimal conditions for the simultaneous separation of two types of drugs in urine,clarified the influence of urine dilution time on the recovery of the two types of drugs and obtained the best conditions Under the optimal condition,LC-MS/MS was used to verify the performance of simultaneous extraction by LPME-EME for the acidic and basic drugs in urine samples.Results:The acidic drugs in the donor phase were extracted into the acceptor phase and the basic drugs were still retained in the donor phase when LPME was carried out alone.When performed EME alone,the basic drugs in the donor phase passed through PPG4000-SLM and entered the acceptor phase under the driving of the electric field,while the acidic drugs migrated into the PPG4000-SLM.In the LPME-EME system,acidic drugs migrated to the acceptor phase of the LPME part,and basic drugs entered the acceptor phase of the EME part.The optimal extraction conditions were as follows:TFA with p H=2 was the sample phase,and the extraction time was 30min.Under this condition,the recoveries of NAP,FLB,DIC,HAL,FLU and SER were 91.98±1.02%,86.68±3.17%,88.37±3.78%,101.34±5.33%,102.65±5.87%and 97.88±3.19%,respectively.The data displayed that the recoveries of acidic and basic drugs were not affected by each other's concentration when using different proportions between the two types of drugs.Finally,the performance of LPME-EME was evaluated by LC-MS/MS for the acidic and basic drugs in urine samples.The results showed that the linearity range of all kinds of drugs was 1?1000 ng m L-1,with R2>0.99,LOD of 0.04?0.22 ng m L-1 and LOQ of 0.15?0.74 ng m L-1.The precision of all of the drugs was less than 9%.Conclusions:In the system of extracting acidic drugs with LPME alone,the distribution of basic drugs was not affected by the extraction conditions;in the system of extracting basic drugs with EME alone,acidic drugs were affected by the p H value of the donor phase and migrated into the PPG4000-SLM.When LPME-EME was performed,acidic drugs and basic drugs were extracted into the corresponding acceptor phase respectively.It showed that in the LPME-EME system,the two extraction methods were independent processes.The recoveries of acidic and basic drugs were not affected by each other's concentration,indicated that the concentrations of both did not interfere with each other during the extraction.The good extraction performance for proposed method showed that the LPME-EME of acidic and basic drugs was a reliable sample pretreatment technique based on PPG4000-SLM in urine samples. |
PDF Full Text Request