Development Of Membrane Assisted Three Liquid Phase Extraction Method And Its Application In HPLC Analysis Of Biogenic Amines And Others In Samples

At present,due to the diversity and complexity of samples with very low concentration,the sample pretreatment became key important step in the whole analysis process.A number of sample pretreatment methods have been established,but these methods have some disadvantages,such as poor stability,low purification efficiency and repeatability,and time consumption etc.Therefore,it is quite necessary to establish a convenient,fast,highly stable and repeatable pretreatment method.In this work,a new membrane assisted three liquid-phase extraction method with high cleaning efficiency,simplicity,stability and sensitivity was established based on the combination of two liquid-liquid extractions by membrane separation.In order to confirm the feasibility and accuracy of the method,phenolic compounds and biogenic amine were extracted from real complex samples such as food and water with medium and even trace amounts of biogenic amines and phenolic compounds were detected by high performance liquid chromatography and liquid chromatography tandem mass spectrometry.This study provides valuable theoretical basis and technical reference for the treatment,evaluation and supervision of phenolic compounds and biogenic amines in wastewater and food sample.The main research contents of this paper are as follows:Firstly,the common sample pretreatment techniques and detection methods were reviewed,and the shortcomings of present pretreatment techniques are pointed out.Secondly,it introduces the research object of phenolic compounds and biological amines,and their harm to human beings and organisms.Finally,the significant,purpose,ideas and highlights of this work was presented.Three liquid-phase extraction and membrane separation were combined to establish a membrane assisted three liquid-phase extraction method.Then the membrane was discussed.Four phenolic compounds were used as example of acidic analytes in this research.Factors affecting the extraction efficiency such as the organic solvent,both pH of donor and acceptor phase and extraction time were optimized.In addition the chromatographic conditions were optimized.The results show that the method has good linearity,accuracy and reproducibility.The recovery is in the range of 74.39-97.07%,and the RSD is less than 3.90.Compared with other pretreatment methods,it has higher cleaning ability,fast,stable,simple and low cost.It is used for the pretreatment of trace phenolic compounds in complex samples.Aiming at the problems of pretreatment methods for higher polar biogenic amines in food,a carrier-mediated membrane assisted three liquid-phase extraction method was established,which can directly detect the content of eight biogenic amines in food without any derivatization.Extraction conditions were optimized,including types of carriers and carrier concentration,pH of donor and acceptor phases,etc.And LC-MS detection conditions included chromatographic and mass spectrometry conditions.The optimum conditions were as follows: D2 EHPA with 0.025 mol/L as carrier,formic acid with 0.4 mol/L as acceptance phase,NaOH with pH=12 as donor phase,rotating speed of 500 rpm and extraction time of 30 min.The content of eight biogenic amines in red wine,apple juice,orange juice and soy sauce was determined under the optimal extraction and detection conditions.The linear range of the method is 0.3-100 ng/mL,the detection line is 0.3-1 ng/mL with less than 1.39 RSD.The recovery rate at 50 ng/mL is 65.52-112%.Compared with other methods,this method avoids the hard derivatization treatment,shortens the time and avoids the pollution of derivatives.Finally,the research results are analyzed and summarized,and the future perspective of the three liquid-phase extraction and the extension of applications are prospected based on this study.