Studies On The Application Of Sample Pretreatment Coupled With HPLC In Chinese Herbal Medicine And Pesticides

In the wake of rapid developments in science and technology,the problem of medicine and environmental safety have been got more and more attention by human being.The hotspot in the field of analysis that it is great importance of trace or microanalysis of drugs or environmental hazards in complex matrix.Due to the complexity of matrix,the diversity of samples and the difference of content,there are many errors and interference factors in the actual separation and analysis process,which greatly affects the accuracy and precision of the analysis results.Hence,Sample pretreatment plays an increasingly vital role in the whole sample analysis process,which will become the key to our ability to obtain accurate and reliable analysis results in the initial step.Chinese herbal medicine has become a bottleneck for scientific researchers because of its variety and complexity.On the other hand,the problem of water pollution in the environment is not only increasingly prominent but also more and more serious.Meanwhile,relying on the existing technology,the the municipal wastewater treatment plant can not completely remove the organic pollutants and inorganic pollutants in the water,especially the residues of organophosphorus pesticides.Once the concentration exceeds the standard,it will cause a serious impact on human health,soil and water.Therefore,it is of great practical significant to analyze and study the components of Chinese herbal medicine and pesticide residues in the field of analytical chemistry.Due to the complex components of Chinese herbal medicine is difficult to separate.And the pollutants in water are difficult to direct determination on account of the low concentration,complex composition,as well as serious interference in the water.It is difficult for the general methods to successfully analyze and determine them directly.Consequently,it is necessary to carry out appropriate sample pretreatment to isolate and enrich the target.It can not only separate the measured components from complex samples and make them into solutions which are easy to determine,but also realize the enrichment of trace substances and improve the sensitivity of the method.More importantly,it can eliminate the interference of matrix on the measured components and improve the selectivity of the methodBased on the essential role of sample pretreatment in analytical chemistry,the separation of Chinese herbal medicine and pesticide was studied and applied.In this paper,the following research work has been carried out by using the high performance liquid chromatography(HPLC)coupled with novel sample pretreatment:1.Simultaneous determination of nine active ingredients in Ginkgo biloba L.by ultrasound assisted-ionic liquid microextraction coupled with reversed phase high performance liquid chromatographySimultaneous determination of caffeic acid,ferulic acid,rutin,chlorogenic acid,quercetin,luteolin,kaempferol,apigenin and protocatechuic acid in Ginkgo biloba L.by ultrasonic assisted-ionic liquid microextraction coupled with reversed-phase high performance liquid chromatography.And the targets were anlayzed by a HPLC system equipped with C18 column(150 mm×4.6 mm,5 μm)and UV detector.The mobile phase was composed of water with the 0.2% acetic acid and methanol at a flow rate of0.5m L/min.The detection wavelength was set at 290 nm.Under optimal conditions,the separation of the nine components was good.The standard curve showed good linearity,and the correlation coefficient r≥ 0.9994(n=8).The average recovery rate(n=3)was 98.40%～103.45%,and the RSD was 0.75%～3.21%.According to the above,this method is simple and reliable,which not only provides a theoretical basis for quantitative detection of Ginkgo biloba L.,but can be used for the quality control of Ginkgo biloba L.2.Dispersive liquid-liquid microextraction coupled with the solidification of a floating organic droplet for the determination of four active ingredients in hawthorn by HPLCA simple dispersive liquid-liquid microextraction(DLLME)coupled with the solidification of a floating organic droplet(SFO)was developed for the determination of four active ingredients in hawthorn before high-performance liquid chromatography with ultraviolet detetion(HPLC-UV).The analytes were firstly extracted from hawthorn into ethyl acetate under the optimized conditions.At the same time,the dispersive liquid-liquid microextraction based on solidification of floating organic droplet procedure was performed by using 1-undecanol with lower density than water as the extraction solvent.The separation of four active ingredients in hawthorn was measured by the high-performance liquid chromatography equipped with a C18 column(150 mm×4.6 mm,5 μm).Methanol and 0.1% acetic acid solution were used as mobile phase at the flow rate of 0.8 m L/min.The detection was performed with a UV detector at 290 nm wavelength.The four compounds were well separated with good linear correlations and correlation coefficient r >0.9993(n=10).The average recoveries were93.65%～99.72%,RSD were between 1.26% and 2.04%.The good performance has demonstrated that the proposed methodology not only simple,reliable,as well as the high extraction efficiency,but provides a theoretical basis for quantitative detection of hawthorn and has a strong potential for application in the multiresidue analysis of complex matrices.3.Liquid-liquid microextraction for the determination of seven pesticides in environmental water samples by HPLCAn improved effective high performance liquid chromatography coupled to a ultraviolet detection(HPLC-UV)was developed for the determination of seven pesticides in environmental water samples in the study.The ionic liquid was used as the extraction solvent and mixed with the aqueous sample solution,thus forming the emulsion under the improved conditions.The targets of the mixed solution were extracted by liquid-liquid microextraction technology.The process was harmless to the environment.Under the optimized conditions,the seven pesticides were well separated.The standard curves were in a good linear curve with the correlation coefficient(r≥0.9993).The results shown that the relative standard deviations(RSD)for tap water and Chongde Lake were 1.88%～4.24% and 2.57%～4.86%,respectively.And the recovery rates of spiked samples was in the range from 95.52% to 97.12% and from 96.90% to 104.06%,respectively.