Study Of High-sensitive Analytical Method Of Typical Antibiotics By Ce And The Matrix Effects Of Environmental Water

As a kind of emerging contaminants named pharmaceuticals and personal care products(PPCPs), antibiotics have aroused widespread concern in both the academic circles and the publicwith the improvement of analytical techniques and public awareness. Even though theirconcentrations are as low as ng/L–μg/L level in environmental water, antibiotics are proved to bepotential ecological risks for aquatic organisms and even for human beings. The researches ofantibiotics in environmental water of China started late, and far from extensive, compared to thosein western countries, as to this, it is significant to detect antibiotics in environmental water.Capillary electrophoresis (CE) as a new and powerful chromatography technique has advantagesof high resolving power, short analysis time, less solvent consumption and flexible separationmodels, which could be applied in many fields and even used in environmental analysis.In this paper, tetracyclines (TCs) and fluoroquinolones (FQs) as typical antibiotics inenvironmental water were chosed to study. The analytical methods of TCs and FQs weredeveloped by CE coupled with UV detector respectively. High sensitive analytical methods ofTCs and FQs were developed by applying CE on-line stacking in order to adapt to environmentalanalysis. In addition, it was the first time to study the matrix effects of environmental waters onanalysis of TCs, such as pH, hardness, metal ions, salinity etc.Chapter one: Firstly, the classification and mechanism, the production and application ofantibiotics, the source of antibiotics in environmental water and its environmental effects wereintroduced. Moreover, the analytical methods of antibiotics in the past were stated. Finally, theprinciple, separation mode, detector and stacking of CE were interpreted.Chapter two: The method of determination four tetracyclines (tetracycline, chlorotetracycline, oxytetracycline and doxycycline) in environmental water by CE-UV was developed. The pH,concentration, additives of background electrolyte (BGE) were optimized for analyzing thestandard mixture sample, meanwhile, the separation voltage was investigated. The goodquantitative linearity and baseline separation within9.0min were obtained for four tetracyclines atthe optimal conditions. It was the first time to study the matrix effects of environmental waters onanalysis of TCs, such as pH, hardness, metal ions, salinity etc. The method was applied todetermine TCs in tap water, pond water, lake water and sewage, there was no TCs detected. Itrevealed the matrix of sewage was very complex which disturbed the determination of TCs.Chapter three: Three injection modes of HDI, field-amplified sample injection (FASI), largevolume sample stacking (LVSS) were used to improve the detection sensitivity in order to satisfyenvironmental analysis of TCs. It turned out that that LVSS has advantages over the other inreducing the LOD. The LOD of four TCs by LVSS was down to8.13-14.5ng/mL with UVdetector (275nm) and the sensitivity was improved to44-fold in comparison with normal HDI.The obtained LOD of LVSS was at the same level with the LOD of the reported methodSPE-HPLC-UV. CE-LVSS reveals a great advantage due to simple sample pretreatment and fastspeed, which can satisfy the determination of TCs in livestock and poultry farms water.Chapter four: The method of determination four fluoroquinolones (norfloxacin, ofloxacin,enrofloxacin and ciprofloxacin) in environmental water by CE was developed. Methyl betacyclodextrin (M-β-CD) was used as additive to separate CIP and NOR which relyed on thedifferent strength of M-β-CD with CIP and NOR. While CIP and NOR cannot be separatedwithout M-β-CD by CZE for they have similar chemical structure. The variety, pH, concentration,and additive of BGE were optimized for analysis of four FQs. The baseline separation of four FQswas achieved within9min at optimal conditions, meanwhile, the good quantitative linearity andRSD were owned. LVSS was applied to improve the analysis sensitivity of four FQs in order tomeet with environmental analysis. The resulted LOD of FQs was down to6.56~8.63ng/mL,which was35~42fold improved compared with normal HDI. Due to the advantages of simplesample pretreatment and fast speed, CE is promising in the analysis of antibiotics inenvironmental water.