| Subcritical water extraction (SWE) use pure water as the solvent and is an innovativegreen sample preparation technique. Subcritical water's polarity can be changed by controllingtemperature and pressure. When the temperature is increased, the polarity decreases, and thesolubility of organic compounds in the subcritical water increases dramatically. Due to itsoutstanding advantages including less use of organic solvent, short extraction time, highsample recovery rate, SWE has been applied to the sample preprapation in many fields.Capillary electrophoresis (CE) has many advantages, such as high efficiency, short analysistime, small sample size and inexpensive instrumentation. It has been widely used for the rapidand efficient determination of active compounds in complex samples. In this dissertation, ananalysis method for alkaloids in Sophora flavescens Ait. was investigated systematically andestablished by SWE-CE. And according to the characteristics of the B-vitamins in the wheat,the B-vitamin contents (vitamin B1(VB1), vitamin B2(VB2), and vitamin B6(VB6)) in thegrains of colored wheat were determined using high-performance liquid chromatography withfluorometric detection. The main results are presented as follows:1. The extraction and determination of cytisine, sophocarpine, matrine, sophoridine andoxymatrine in Sophora flavescens Ait. were performed using subcritical water extraction andcapillary electrophoresis coupled with field-amplified stacking. The effects of extractiontemperature, pressure, time and cycle number on the extraction yields were investigatedsystematically for accelerated solvent extraction with ethanol (ASE) and accelerated solventextraction with water (subcritical water extraction, SWE). The extraction yields obtainedusing SWE, ASE, water ultrasonic extraction and chloroform soaking extraction methodswere compared. The subcritical water extraction exhibited the highest total alkaloid yields.The electrophoresis separation buffer was monosodium phosphate (pH3.0;110mM)-isopropanol (85:15; v/v). The effect of phosphoric acid added in the sample matrix on thereproducibility of the peak heights of the analytes was also examined. Cytisine, sophoridineand oxymatrine showed good linearity (R2>0.999) within125-4000ng/mL, and sophocarpine and matrine exhibited good linearity (R2>0.998) within62.5-2000ng/mL, with the detectionlimits in the range of4-1.3ng/mL. The five alkaloid contents in medicinal plants fromdifferent sources and Sophora instant granule were determined and compared. By integratingSWE and CE, we attempted to provide a new, efficient and environmentally friendly analysisapproach for the medicinal plant quality control.2. Color wheat is a valuable germplast resource, as a nutritious composition study ofsuch has shown potential implications for plant breeding. In this study, the B-vitamin contents(vitamin B1(VB1), vitamin B2(VB2), and vitamin B6(VB6)) in the grains of12colored wheatvarieties were determined using high-performance liquid chromatography with fluorometricdetection. And the relationships between the kernel pigment content and the contents of the Bvitamins, the kernel weight and the contents of the B vitamins, as well as the relationshipsamong the contents of the B vitamins were studied. The results showed that in wheat kernels,the contents of VB1, VB2, and VB6were2.85-4.08μg/g,0.78-0.85μg/g, and3.94-5.26μg/g,respectively. For kernels of the same color, those with high pigment contents had lower Bvitamins contents; therefore, the pigment contents of the kernels were inversely correlatedwith the B vitamin contents. The kernel weight also showed an inverse correlation with theVB6content, while the VB1content showed a positive correlation with the VB6content,regardless of the kernel color. For kernels of the same color, the correlations between the VB2and VB1contents were positively correlated, and so was the correlations between the VB2andVB6contents. |
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