The Theory Study Of A New Microextraction Technology And Its Application In Complex Matrix Sample

In recent years,the detection of trace drugs in complex sample matrix become bottlenecks in the development of pharmaceutical analysis,establishment and development of a new sample pretreatment technology has becomes a research hot spot for analysis scholars.As is well known,based on the low drug concentrations,high biological activity and wide pollution,to meet the requirements of analysis,we not only need to enrichment the trace components,but also separate them from the complex matrix,improving the detection sensitivity.At present,traditional preparation method such as liquid-liquid extraction(LLE),solid phase extraction(SPE)only play a role of separation,purification,and have the shortcomings of complex operation,takes longer,more organic solvent consumption.Therefore seeking a sample pretreatment technology with high concentration,high purification,simple operation,less organic solvent for the determination of trace drugs in complex matrix is particularly important.Due to the high concentration,purification ability and use a small amount of organic solvents,HF-LPME method is widely used in pharmaceutical analysis field.However,for the method,suitable solvent extraction directly influences the extraction efficiency of the object analytes.In order to choose the optimal extracting solvent,scholars do a lot of work and take a lot of time.Our study select six β-blockers as a model drugs,a series of alkyl alcohol as extracting solvents to explore the relationship between extraction efficiency and the anaytes,extraction solvent further to guide all analytes to screen the optimal extracting solvent.The experimental results show the extraction efficiency is not only influenced by the polarities of extraction solvents and analytes,pH of sample solution and the pKa of analytes also exert influence on the extraction efficiency.The proposed model offers a helpful guidance for the selectivity of the appropriate extraction solvent for interests to obtain maximum EE in a short time,which greatly reduces the number of experiments.Meanwhile,it provides theoretical basis for further development of LPME method.With increasing utilization of pharmaceuticals and continuous expansion of the pharmaceutical industry scale,more and more organic pollutants1 are being discharged into the environment from wastewater effluents.Although long-term ecotoxicological effects remain unclear,most of them are biologically active compounds which inevitably harm directly or indirectly the environment and humanity.B-blockers are one among the most widely prescribed medicines worldwide.They are popularly used in the treatment of hypertension,angina pectoris and are detected in aqueous environments frequently.Due to low concentrations of pharmaceuticals and high interference in complicated sample matrices,in order to improve the selectivity and sensitivity of analytical methods,sample pre-concentration and clean up processes are very necessary.The proposed technique was successfully applied for screening multiple β-blockers in complex aqueous samples and provided a simple and reliable new means for the self-checking of laboratories at the basic level.The cycle of the treated wastewater is a kind of circular economy behavior,especially in the case of water resources are increasingly tense and water pollution is increasingly aggravating in today’s world.The reuse of industrial wastewater and urban sewage has gradually become China’s economic sustainable development process in the face of one of the most important issue which becomes a very important subject.Thus,constantly improving the efficiency in recycling water becomes the inevitable trend of development.However,with low concentration of contaminants and complex composition of wastewater,if the sample is analyzed directly,analyte matrix not only interferes with the determination of the analytes,but also badly influences the performance of the chromatographic system,greatly reducingthe sensitivity and accuracy of the method.Therefore,sample preparation method is necessary.HF-LPME with highly selective and clean-up ability was applied widely especially for the complex sample matrix.However,for the method,it really is a time-consuming technique,typically takes 30 min-8 h.A long period of pretreatment particularly is unsuitable for the quick-detection of wastewater.Our research established a novel sample preparation technique(EME),to achieve a low limit of detection(LOD),a new device of EME by increasing the number of hollow fibers from one to two was developed,significantly increased the sensitivity of the method.PART 1 Study and Application of HF-LPME Pretreatment Technology in Pharmaceutical Analysis一、 The Theory Study of LPME Pretreatment Methods in Complex Sample MatrixObjective : The selectivity of a suitable organic solvent is key in liquid-phase microextraction experiments.Nevertheless,the screening process remains a daunting task.Our research aimed to study the relationship between extraction efficiency and extraction solvents,analytes,and finally select the appropriate extraction solvent.Method: In the present article,β-blockers and six extraction solvents were chosen as the models.Factors affecting extraction efficiency including the logarithms of the octanol/water partition coefficient(logPo/w)of analytes,acid dissociation constants,the logarithms of the octanol/water partition coefficient of solvents and pH of the sample solution were investigated.Results: The results showed that a low water solubility of extraction solvent is the foundation to ensure higher extraction efficiency.Moreover,when logPo/w > 0,a higher extraction efficiency is observed at lower logPo/w,on the contrary,when logPo/w < 0,extraction efficiency is higher as the absolute value of logPo/w becomes greater.Conclusion: Finally,the relationship between enrichment factor and extraction solvents,analytes was established and a helpful guidance wasprovided for the selection of an optimal solvent to obtain the best extraction efficiency.二、 HF-LPME followed by HPLC for simultaneously screening multiple trace level β-blockers in environmental water samplesObjective: A sensitive two-phase hollow fiber liquid-phase microextraction(HF-LPME)pretreatment technique was developed for simultaneously screening multiple β-blockers in environmental samples.Method:Heptanol was chosen as the extraction solvent.The fundamental parameters affecting the extraction efficiency(EE)including extraction time,temperature,pH of the donor phase(DP)and AP,stirring speed,ionic strength were studied and optimized.Results: Under optimal conditions,good linearity was in the range of0.16-200 ng/mL,limits of detection(LODs)were between 0.08 and 0.5ng/mL,the intra-and inter-day precision values of the six β-blockers were 1.0-2.2%and 1.4-2.7%,respectively.The recovery with RSDs was less than 2.2%.Conclusion: The proposed technique was successfully applied for screening multiple β-blockers in complex aqueous samples and provided a simple and reliable new means for the self-checking of laboratories at the basic level.PART 2 the Study and Application of Electric Membrane Microextraction Technology in Pharmaceutical Analysis一、A novel electric membrane extraction method is used for monitoring a variety of trace β-blockers in wastewater discharged from drug production enterprisesObjective:This paper proposes the use of multiple hollow fibers for the separation and enhancement of three β-blocker drugs by electromembrane extraction performance for the first time.Method:analytes were migrated from donor solutions into the 30 μL acidic acceptor solution(pH=1),which 2-nitrophenyl octyl ether(NPOE)impregnated on the wall of the polyvinylidene fluoride(PVDF)membrane as the supported liquid membrane.For the method,the fundamental experimentalparameters such as supported liquid membrane,extraction voltage,extraction temperature,extraction time,pH values of sample and acceptor solution,stirring speed and salting-out effect were separately investigated and optimized.Results: Analysis was carried out using high performance liquid chromatography after extraction of the analytes.Experiments reported enrichment factors of β-blockers were 117.Under the most favorable conditions,good linearity over a concentration range of 1.60–1000 ng mL-1with correlation coefficient was 0.9998,limits of detection(down to 1.2ng/mL),the precision of extraction(RSD below 3.0%)were obtained.Conclusion: The proposed technique as a fast、simple and effective mean is very suitable for the self-checking of trace pollutants in wastewater from pharmaceutical producing enterprises and wastewater detection taking efficiently.