The Application Of High Performance Capillaiy Electrophoresis In Food And Drug Analysis

Capillary electrophoresis (CE) has been successfully applied to the field of food,biology, medicine and environment due to its advantages of simple sample preparation，short analysis time，minimal use of reagent and low cost. Recent years, food andmedicine ana1ysis has become a focal point of the analytical chemistry as more attentionhas been paid to the quality of life. At present, chromatography is the most commonlyused methods, such as thin layer chromatography (TLC), high performance liquidchromatography (HPLC) and gas chromatography (GC). However, these methods usuallyhave shortcomings of high cost and large organic reagent consumption. In addition,traditional solid phase extraction and liquid-liquid extraction methods were usuallyapplied to sample preparation. Therefore, in this thesis the combination of environmentfriendly sample pretreatment technology with CE was proposed; the application ofexperiment design and quantitative structure-nature relation relationship (QSPR) inprediction of CE separation results was investigated; and several CE methods of food anddrug analysis were developed. In comparison with HPLC, it was indicated that CE can beused as a good alternative in food and drug analysis.In chapter1, the history, the basic theories and the separation modes of CE are brieflyintroduced. The application of CE in food and medicine analysis has been reviewed.In chapter2, a capillary zone electrophoresis method was proposed for simultaneousdetection and quantification of three tetracycline antibiotics in commercial milk samples,i.e., tetracycline, oxytetracycline, and doxycycline. The influences of the electrolytecomposition, pH, as well as temperature and applied voltage on separation wereinvestigated. Matrix solid-phase dispersion procedure was used for sample pretreatment.Several solid support materials were investigated, and C18was used as sorbent.Electrophoretic analysis was completed in less than6min, and the precision, limits ofdetection, accuracy and quantification were satisfactory.In chapter3, a simple method using capillary electrophoresis (CE) was developed fordetermination of BP in wheat flour. BP was determined as benzoic acid after preceding reduction by potassium iodide, and the separation was completed in less than7min. Themethod was validated in terms of linearity, sensitivity, detection limit, precision andaccuracy. The performance of the CE method was comparable, and the quantitative resultswere in good agreement with those using high-performance liquid chromatography(HPLC). Meanwhile the proposed CE method has the advantages of better resolution,shorter analysis time and lower cost, and would be a good alternative to HPLC for routinemonitoring of BP amount in wheat flour.In chapter4, a simple CE method for analysis of NA and NAM was developed.Important experimental factors were optimized with response surface approach. Themethod was applied to the determination of NA and NAM in different kinds of sampleswith satisfactory separation in less than5min. A comparison with HPLC demonstratedthat the developed CE method was comparable with regard to linearity, sensitivity,precision and accuracy, but the analysis time and reagent consumption for CE weredecreased significantly. Experimental design, specifically surface response methodology isan effective optimization method for CE.In chapter5, a simple capillary electrophoresis (CE) method with UV detection wasdeveloped for the determination of four purines including adenine, guanine, hypoxanthineand xanthine in soybean milk. Separation of the four purines was achieved in5min, andboth the linearity and repeatability of the method were good. Acid hydrolysis was usedas sample preparation approach, and was investigated with respect to its extractionpotential of the investigated compounds. Effects of several important factors such as thetype and volume of applied acid, hydrolysis temperature and time were investigated. Theproposed method was successfully applied to determine the purines in different kinds ofsoybean milk samples. Furthermore, a comparison of the results obtained by the proposedCE method was made with those of high-performance liquid chromatography (HPLC).The performance of CE was comparable, and the quantitative results were in goodagreement with those by HPLC, while the CE method has the advantages of much shorteranalysis time and lower cost than HPLC. In chapter6, a simple, fast and low-cost method was developed and validated for theseparation and determination of neostigmine metilsulfate (Neo), naphazolinehydrochloride (Nap), chlorphenamine maleate (Chl), pyridoxine hydrochloride (Pyr) anddipotassium glycyrrhizinate (Dip) by capillary electrophoresis for the first time. Theseparation was achieved in7min, and the method was successfully applied to thequantitation of the five components in a commercial eye drops. Furthermore, a comparisonof the results obtained by CE was made with those obtained by high-performance liquidchromatography (HPLC) described in Chinese Pharmacopoeia. The performance of theproposed method was comparable, and the quantitative results were in good agreementwith those by HPLC, while the CE method has the advantages of much shorter analysistime and lower cost than HPLC.