The Establishment Of Novel Extraction Method And Its Application In Plant-derived Foods

Plant-derived foods are usually used as a component of human diet. However, common plant dietary contains many secondary metabolites and its matrix interference is large. Therefore, the development of modern sample-preparation techniques becomes very important in the analysis of plant-derived foods. In this article, we focused on the establishment of novel extraction methods, which can make the whole analysis process more selective, more sensitive and more environmentally friendly. Additionally, we discussed new sorbent materials and new chromatographic methodologies involved in the analysis of phytochemicals. The main contents were as follows:1. The establishment of miniaturized solid phase extraction (SPE) and its application in the determination of six flavanones in Citrus fruits with ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry was developed. It was the first time using the mesoporous molecular sieve (SBA-15) as a solid phase sorbent. Under the optimum condition, the detection limit (LOD) calculated based on signal-to-noise ratio of 3 was less than 4.26 ng/mL. The repeatability assessed by three parallel SPE extractions of a sample solution was ranged from 2.28% to 5.47% for peak areas.2. The application of trace-chitosan-wrapped multi-walled carbon nanotubes in dispersive micro solid-phase extraction (DMSPE) was proposed to analyze phenolic compounds in chrysanthemum tea and chrysanthemum beverage. All the influencing parameters, such as the sorbent amount, the diluent pH, extraction time and the elution solvent type, were optimized in the DMSPE procedure. Analytical performance of the method was investigated in terms of linearity (2-600 ng/mL, r2> 0.9960), precision (intra-day<1.31% for peak areas, and inter-day< 6.26% for peak areas), sensitivity (LODs=0.22-16.19 ng/mL), and accuracy (recovery=89-106%).3. A novel and environmental friendly sample preparation technique based on the use of methyl-β-cyclodextrin was first developed for the extraction of phenolic compounds from different jujube tissues, and the target analytes were analyzed by ultrahigh performance liquid chromatography with electrochemical detection. Compared with the Pharmacopoeia heat-reflux approach, the present method exhibited higher efficiency for extracting phenolic compositions. Moreover, under the optimized conditions, the proposed method presented good linearity (r2> 0.9970), satisfactory recovery (85.63-105.67%) and low LODs (4.92-142.85 ng/mL).