The Application Of New Sample Pretreatment Techniques In The Analysis Of Chinese Medicinal Material And Environmental Water Samples

Traditional Chinese medicine (TCM) is the treasure of China, and water is the source oflife. As the precious historical of China, TCM is widely welcomed for its unique efficacy.Water, as essential survival resources, is of great significance to human beings. So the qualityof TCM and water is of great importance. Sample pretreatment is one of the most importantaspects for the analysis of samples. In this paper, two new sample pretreatment methods wereproposed for the analysis of TCM and environmental water samples. This thesis is dividedinto four chapters, the contents are as follows:Chapter1: Current existing pretreatment sample methods were reviewed. Specialemphasis was placed on the extraction method of the rhubarb and mangnolia officinalis. Atthe same time, the background and purpose of the study as well as the basic content of thisarticle were elaborated.Chapter2: A new method based on undecane alcohol/acetonitrile/water dispersionsystem extraction and liquid chromatography has been developed and used for extraction anddetermination of five anthraquinone derivatives in the rhubarb. The effects of type andvolume of extraction agent, type and volume of dispersing agent, the amount of sodiumchloride, pH, granularity, the ratio of liquid and solid and ultrasonic extraction time on theextraction efficiency were evaluated. Under optimum conditions, i.e.0.3mL1-undecanol,2.5mL ethanol,0.4g sodium chloride, pH3.1,0.110-0.154mm, liquid/solid ratio of10:300(mL/mg), ultrasonic-assisted extraction for50min, the extraction yield reached the highestvalue. The limits of detection (LOD) for the five anthraquinone derivatives were in the rangeof2.4-8.5ng/mL. Relative standard deviations for six replicate determinations of rhubarbsample were below6.25%.Chapter3: A novel undecane alcohol/acetonitrile/water dispersion system extractioncoupled with high performance liquid chromatography method was developed for thedetermination of honokiol and magnolol in Cortex Magnoliae Officinalis. Variousexperimental conditions were investigated to optimize the extraction process. Under optimumconditions, i.e.0.4mL1-undecanol,2.5mL acetonitrile,0.4g sodium chloride,0.088-0.110mm, liquid/solid ratio of10:150(mL/mg), ultrasonic-assisted extraction for20min, theextraction yield reached the highest value. The limits of detection (LOD) for honokiol andmagnolol were20.6and51.0ng/mL respectively. Relative standard deviations for six replicate determinations of Cortex Magnoliae Officinalis sample were below2.06%.Chapter4: A novel method was established for the analysis of carbamate pesticides inenvironmental water samples by using graphene based solid phase extraction combined withultra high performance liquid chromatography-tandem mass spectrometry. In this paper,graphene, a new sorbent material, was synthesized and used for solid-phase extraction (SPE)of the six carbamate pesticides (pirimicarb, baygon, carbaryl, isoprocarb, baycarb anddiethofencarb) in environmental water samples. Six carbamate pesticides as the targetanalytes can be extracted on the graphene-packed SPE cartridge, and then eluted with acetone.The eluate was collected and dried by high purity nitrogen gas at room temperature.1mL of20%(v/v) acetonitrile aqueous solution was used to redissolve the residue. The final samplesolution was analyzed by ultra performance liquid chromatography-tandem quadrupole massspectrometry (UPLC-MS/MS) system. Some important parameters, such as type of eluentsolvent, the volume of eluent, pH of the sample and sample volume were investigated andoptimized. The optimum conditions were as follows:50mL of sample,5mL of acetone andno adjustment of sample pH. Under optimum conditions, good linearity was obtained for thecarbamates with correlation coefficient in the range of0.9992-0.9998. The limits of detection(LODS/N=3) for the six carbamate pesticides were in the range of0.5-6.9ng/L. Relativestandard deviations (RSD) for five replicate determinations were below5.54%. RSD valuesfor cartridge-to-cartridge precision (n=7) were in the range of1.27%-8.13%. After properregeneration, the graphene-packed SPE cartridge could be re-used over100times for standardsolution without significant loss of performance. The enrichment factors for the targetanalytes were in the range of34.2-51.7.