Microextraction Combined Technology Based On Cucurbit[n]urils Used For The Determination Of Pesticide Residues From Vegetables And The Effective Components Content In Oroxylum Indicum(L.)Vent.

A new method combining matrix solid phase dispersion(MSPD)and dispersive liquid-liquid microextraction(DLLME)is optimized by stoichiometry,and is applied to the extraction,purification and determination of benzimidazole fungicides residues in vegetables.Q[7]was used as MSPD extraction agent to selectively extract carbendazim thiobacillam and methyl thiobacillam from vegetables and transfer them to aqueous solution.Then acetonitrile and chloroform were used as dispersants and extractants respectively in DLLME for further enrichment.Two-level total factor design and central point design effect surface method(CCD-RSM)were used to optimize the extraction process.The established method(MSPD-DLLME-HPLC-UV)shows good linearity in the range of 0.025-5μg/g,R~2>0.9991;The intra-day precision is 5.3%-10.9%,the intra-day precision is 10.6%-15.6%,and the detection limits are0.004-0.007μg/g.The method is applied to the analysis of four different types of vegetables,and the recoveries ranged from 65.4%to 124.0%.The results show that the method is environmentally friendly,simple and sensitive.A simple,rapid and environmental method named column-free matrix solid-phase dispersion(FMSPD)has been investigated for the extraction of three flavonoids(oroxin A,oroxin B and baicalein)from the seeds of Oroxylum indicum(L.)Vent.In this study,cucurbit[8]uril was used as the sorbent of FMSPD to selectively extract three flavonoid compounds and transferred them into an aqueous solution for direct determination using HPLC-UV based on the recognition interaction of cucurbit[8]uril toward the compounds.The variables that influenced the extraction efficiency were investigated,which include the amount of cucurbit[8]uril,grinding time,volume of water,and p H of the solution.A good linearity is exhibited with correlation coefficients>0.9991 for all three flavonoids.The intra-and inter-day precisions are 1.7%-2.6%and3.1%-5.5%,respectively,and the limit of detection is between 0.1 and 0.18μg/m L.Under the optimized conditions,the recoveries are 83.4%-101.4%,and the relative standard deviations are 1.1%-6.8%.The developed method is applied to analyze four kinds of Semen Oroxyli from different regions of China.F-and t-tests show that the results have no significant difference when comparing the traditional ultrasound-assisted extraction method to the novel FMSPD extraction method,but the method is simpler,faster and is not use organic solvents.