New Pretreatment Methods For Algal Toxin MC-LR And Glycopeptide Antibiotics In Water

Microcystins(MCs)are a class of toxins produced by freshwater blooms.MC-LR is a known type of algal toxin that has the highest frequency,the strongest toxicity and the widest pollution range in cyanobacterial blooms.Glycopeptide antibiotics,because of their good effects on the treatment of penicillin-resistant bacteria,have a wider range of applications.Even low-concentration glycopeptide antibiotics in water can cause bacteria resistance,which may have adverse effects on the whole ecosystem.Therefore,it is more and more important to strengthen the detection and control of MC-LR and glypeptide-based antibiotics in the water environment.However,they are easily soluble in water and exist in trace forms in natural water bodies,making their detection and analysis difficult.It is usually necessary to take some pretreatment measures for separation and enrichment before detection.In this study,two magnetic solid phase extraction and high-performance liquid chromatography(MSPE-HPLC/UV)technologies were established for the separation and identification of MC-LR and glycopeptide antibiotics(vancomycin was taken as the research object).The applicability of the method was explored by extraction material preparation,pretreatment conditions optimization and method performance evaluation.The main research contents and conclusions are as follows:In this study,LN/PAN-based mesoporous carbon fiber(HPCF)was successfully prepared.The nano-material is a fibrous material with many mesoporous structures with a specific surface area of 1331.3~1346.4 m~2/g.It was modified as a matrix material and applied to the pretreatment extraction of MC-LR and glycopeptide antibiotics,respectively.The magnetic mesoporous carbon fiber(m-HPCF)modified by coprecipitation was used for MC-LR pretreatment,and the pretreatment conditions were optimized to determine the magnetic solid phase extraction conditions.The MSPE-HPLC combined technique has a good linearity in the range of 0.1~10μg/L for the isolation and identification of MC-LR.The LOD is 0.1μg/L,and the RSD value is less than 5.2%.The detection limit can meet the drinking water in China Standard control requirements.The m-HPCF-APBA material was prepared by modifying the boronic acid group on m-HPCF by click polymerization.The successful synthesis of the material was confirmed by SEM,XRD,FT-IR and BET.The new extraction material m-HPCF-APBA exhibits specific adsorption properties in the direction of isolation and identification of glycopeptide antibiotics,and has pH response performance.It exhibits good adsorption capacity for glycopeptide antibiotics in an environment of pH=9.0,and can be eluted under acidic conditions.Pretreatment of glycopeptide antibiotics with m-HPCF-APBA established a simple,highly efficient and sensitive method for the separation and detection of trace glycopeptide antibiotics in environmental water.The method was validated by method,and the linear relationship of vancomycin in the concentration range of 0.01~100μg/mL was good(R~2=0.999).The LOD is 0.01μg/mL,the LOQ is 0.029μg/mL,and the RSD is within8.1%.The MSPE-HPLC/UV analysis methods of this study were compared with other methods,and the actual water samples of different matrices were spiked with MC-LR and glycopeptide antibiotics to investigate the recovery and precision of the method.The results show that the recovery and accuracy are high under the interference of different substrates.The method established in this study has good applicability and provides a new method for the isolation and identification of MC-LR and glycopeptide antibiotics in environmental water.