Study On Determination Method For 24 Antibiotics In Aquatic Environmental Samples And Its Application

With the rapid development of livestock agriculture and aquiculture,the types and dosage of antibiotics are keeping on increasing.The antibiotic residues in animal products have not only caused food safety problems,but also imposed pressures on environmental health and ecosystem security,as considerable amount of them being released into water environment through the disposal of animal feces,medical wastes and direct feeding jettison.In this work,a method for simultaneous determination of 24 commonly used antibiotics in river and sea water samples using solid phase extraction and ultra performance liquid chromatography coupled with electrospray tandem mass spectrometry(SPE-UPLC-MS-MS) has been developed and successfully applied to survey the distribution of taget antibiotic residues in Jiulong River estuary and Xiamen coastal area.The research contents and results are as the followings:(1) Establishment of Simutaneous detection method for 24 antibiotics using ultra performance liquid chromatography coupled with electrospray tandem mass spectrometryA high sensitive,accurate and effective method for the simultaneous detection of 24 antibiotics using ultra performance liquid chromatography with electrospray tandem mass spectrometry(UPLC-MS-MS) under multiple reaction monitoring mode(MRM) was developed.The effects of composition and gradient elution program of the mobile phase on the separation and MS parameters,such as capillary voltage,cone voltage and collision energy were investigated and optimized.Under the optimized conditions,the detection limits of antibiotics all reached 0.5μg/L,except tetracyclines at 10μg/L.The linearity ranges of chloramphenicols,tetracyclines,quinolones and sulfonamides were 0.5 to 1000.0μg/L,10 to 1000.0μg/L and 0.2 to 1000.0μg/L,respectively.The correlation coefficients were all between 0.9982 and 0.9999.The method is high sensitive, reproducible,simple and fast(24 target antibiotics were divided into three groups and the entire detection process could be accomplished within 1 h).(2) Development of solid phase extraction method for simutaneous extraction of 24 antibiotics from river and sea water samplesA simple and enrichment/cleanup-effective solid phase extraction method for the simultaneous extraction of 24 antibiotics in river and sea water samples using HLB cartridge was developed.The enrichment and cleanup effects of 5 different types of SPE cartridges were compared,and various influential factors such as pH and salinity of water samples,breakthrough volume,flow rate and the elution solvent and volume,were investigated.Under the optimized conditions,recoveries and relative standard deviations(RSD,n = 4) at 5.0 ng/L,20.0 ng/L and 100.0 ng/L spiking levels were 50.1%～94.7%,1.6%～9.7%for river water matrix, 46.7%～81.2%,4.8%～9.4%for seawater matrix,respectively.The method detection limits of target antibiotics could reach 1.0 ng/L,even lower with the exception of tetracyclines at 20 ng/L.Using surrogates as quality control method, the proposed method could meet the requirement for detecting trace antibiotic residues in aquatic environments.(3) Distribution survey of 24 antibiotics in Jiulong River estuary and Xiamen coastal area surface waterThe existence and distribution of 24 antibiotics in Jiulong River estuary and Xiamen coastal area surface water were surveyed in December 2006 and April 2007 using established SPE-UPLC-MS-MS method.Results indicated that florfenicol(2.1～23.0 ng/L),sulfadiazine(1.8～162.7 ng/L),sulfamethazine (1.7～153.3 ng/L),sulfamonomethoxine(1.5～50.2 ng/L) and sulfamethoxazole (4.2～40.8 ng/L) were detected in all of the 28 sampling stations,chloramphenicol (0.5～5.9 ng/L) and sulfameter(1.2～11.3 ng/L) were detected in most sampling stations,thiamphenicol(1.0～2.6 ng/L) and sulfapyridine(0.3～2.0 ng/L) were found only in sampling stations near Jiulong River esturary,and ofloxacin(0.9～5.8 ng/L) was found only in sampling stations near Xiamen coastal area. Compared with the research results from foreign countries,the status of antibiotic pollution in Jiulong River estuary and Xiamen coastal area should be of great concern.