| Antibiotics are widely used in our day-to-day production and life. Their widespread existence leads to pathogens’ drug resistance. Some antibiotics have shown carcinogenic, teratogenic, and mutagenic effects, allergies to sensitive people, and adverse influences on human health, ecological environment and product quality. SPE is an essential procedure of detection of antibiotics in environment. Mono-dispersed polymeric microspheres with high specific surface area and some polarity are widely applied to detection of trace organic pollutants in environment. Mono-dispersed polymeric microspheres are generally synthesized by homogeneous polymerization, seeding polymerization, etc. Membrane emulsification and suspension polymerization has also been used to synthesize mono-dispersed polymeric microspheres in recent years.In this study, mono-dispersed polymeric microspheres of different diameters (2.6～40μm) were prepared bythe method of membrane emulsification and suspension polymerization. Influence law of the factors that impact diameter dispersion of polymeric microspheres was analyzed, including transmembrane pressure, membrane pore size, etc. Test results showed that transmembrane pressure was the crucial factor to control diameter dispersion and smaller membrane pore size or smaller membrane flux needed higher pressure while a linear correlation was found between microsphere diameter and membrane pore size. Influence law of the proportion of cross-linking agent and post-cross-linking mode that impact pore size and surface property of final polymeric microspheres was studied. Test results showed that microsphere’s surface polarity was enhanced and specific surface area greatly increased after post-crosslinking. Compared with using dichloroethane, microspheres using nitrobenzene as sweller had relatively higher surface polarity and capacity of various solvents. The resin microsphere material of K5whose diameter was40μm for off-line Solid-Phase Extraction (SPE) and K3whose diameter was7μm for on-line SPE were screened out.Determination methods of quinolones, sulfonamides and tetracyclines using ultra performance liquid chromatography coupled with triple quadrupole mass spectrometry were developed by optimizing chromatography and mass spectrometry conditions. Applying hypercrosslinked SPE materials to preconcentration and separation ofoff-line SPE of trace antibiotics in waters was undertaken by optimizing the conditions of pH, eluant and its flow rate. Test results showed that the best eluant was acidified methanol, the best velocity was5-15mL/min, and the best pH of samples into off-line SPE is3. The SPE column of K5microsphere obtained relatively effective preconcentration and separation of tetracyclines and chloroamphenicol at recovery rates higher than75%, which is equivalent to Oasis HLB column and higher than C18column. K5column also obtained recovery rates of sulfonamidesand quinolones higher thanC18column, but lower thanHLB column. Its penetration volum was about3500mL while the penetration volum of the commercial SPE column of Oasis HLB was about3000mL. Recovery rates of actual water samples using the hypercrosslinked resin SPE column of K5were in the range of28.3%-96.6%, among which the recovery rates of tetracyclines and chloroamphenicol were in the range of76.5%-96.6%, suitable for actual water sample analysis with detection limits between0.5ng/L and3ng/L,almost equal to that of HLBcolumn (between0.5ng/L and5ng/L).On-line SPE columns were successfully filled with the synthized resin microspheres of K3and applied to preconcentration and separation of antibiotics and brominated flame-retardants. pH of samples into on-line SPE and elution conditions of chromatography were optimized. The best pH of samples into on-line SPE is7. The SPE column of K3microsphere obtained relatively effective preconcentration and separation of tetracyclines at recovery rates higher than75%, which is higher thanOasis HLBcolumn. Detection limits were between20ng/L and100ng/L, almost equal to that of HLBcolumn (between5ng/L and100ng/L), which could meet the detecting requirements of some samples.K3columnalso obtained recovery rates of quinolones lower thanHLB column, and recovery rates ofsulfonamideshigher thanHLB column.Characteristics of selected antibiotics in some important water bodies of Taihu Lake Basin were obtained based on establishment of reliable detection methods. Results showed that different kinds of antibiotics were identified in water samples from different kinds of sites. It was probably related with aquaculture that sulfonamides and tetracyclines were identified in lake and reservoir; it was probably related with people’s daily life that sulfadiazine and chloromycetin were identified in sewage treatment plant; it was probably related with livestock and poultry breeding that ciprofloxacin and sulfamethazine were identified in suburb river. |
PDF Full Text Request