The Determination Of Several Drug Residue In Food By The Concentration Techniques In Capillary Electrophoresis

In recent year, there are a growing attation on the problem of drug residue including human drug and animal drug, for they tend to accumulating through food-chain and presenting the public health concerns because of the huge and improper usage. Therefore, scientific interest of developing improved analytical methodologies with the aim of increasing sensitivity and rapidity of analysis for drug residue in food is growing. And the most commonly used technique employs high performance liquid chromatography tandem mass spectrometry detection for its unique high sensitivity as well as robust qualitative and quantitative properties; however, they are not widespread due to rather expensive instrumentation for common laboratory. Capillary electrophoresis (CE) has also been applied to the field of analysis of drug residue in food owing to its excellent separation efficiency, rapid and low-cost analysis, minimal need of samples and solvents. However, as is well known, CE with UV detector suffers from limited concentration sensitivity due to the short light pathlengths and nanoliter sample injection volume. Sensitivity limitations may be overcome by on-line or off-line pretreatment techniques. In this thesis, a CE method with concentration techniques was established for determine selected pharmaceuticals and personal care products (PPCPs) in water samples and sulfonamides and floxacin drug in food matrices. Specific results as follows:1. PPCPs residue in water sample is emerging problem and has drawn widespread attention. Four selected PPCPs including salbutamol sulfate, cimetidine, ibuprofen and carbamazepine can hardly be separated simultaneously by a conventional single C18HPLC column because of its relatively wide range of polarity (logP from0.4to3.97). In this work, a method using CE separation and UV detection with solid phase extraction (SPE) pretreatment for the determination of these compounds in water samples has been developed. Separation parameters, such as running buffer type, concentration, pH, and sample solvent in CE analysis were optimized. Under the optimized condition which was using20mmol/L phosphate solution at pH6.70as running buffer,10mmol/L phosphate with20%v/v methanol as sample solvent, all analytes were well separated. This method showed good linearity of3.0-20.0mg/L, satisfactory method detection limits (MDL) of1.3-2.9μg/L and reproducibility of method (the RSD was less than5%, n=7). The recoveries of four analytes spiked in water samples ranged from89.7to108%. Water sample including drinking water、pond water and wastewater were collected and analyzed. The results demonstrated that the developed method was simple, low-cost, which may work as a potential alternative method for the determination of some PPCPs.2. It is difficult to choose a proper on-line preconcentration technique for the determination of selected PPCPs because of their variety. In this work, an on-line preconcentration technique, namely sweeping, has been employed in order to obtain more sensitive analysis for salbutamol sulfate, cimetidine, ibuprofen and carbamazepine with different ionization (positive, neutral and negative). Separation conditions after optimization were as following running buffer,20mmol/L boric-50mmol/L SDS, pH8.35,2mmol/L (1R,2R)-(-)-1,2-diaminocyclohexane (R-DACH); separation voltage,10kV; injection,35mbar inject40s. Under the optimized conditions, the result shown that sweeping on-line preconcentration can be applied for selected PPCPs determination coupled with off-line pretreatment SPE which reduced the volume of loaded water sample.3. Sulfonamides and floxacin drug are important synthetic antibiotics that have been widely used as veterinary drugs for animals. In this work, field-amplified sample stacking (FASS) on-line preconcentration technique has been developed for determining four sulfonamides and two floxacin drug in honey and chicken samples. Under the optimized condition which was using30mmol/L phosphate solution at pH7.5as running buffer,5%v/v methanol as organic additive,0.1mmol/L NaOH as sample solvent, injection time was electrokinetic injection20s at-8kV. Chicken sample pretreated by liquid-liquid extraction and honey samples pretreated by SPE. The results shown that for chicken, there are only four analytes (sulfacetamide sodium, sulfadiazine, sulfamerazine, pefloxacin) due to the interference by unknown impurity, and the recovery of pefoxacin is low maybe caused by the reverse extraction and matrix effect. For honeys, there are many unknown impurities which have interference in the analyte peak after FASS, therefore, FASS on-line preconcentration technique hardly applied in the determination of honey samples, and SPE with CE can be applied to determine sulfonamides and floxacin drug in honeys.