Liquid Phase Nanoextraction Technology And In-situ Analysis Of Phytohormones

In-vivo and in-situ detection is one of the frontier research hotspots of analytical chemistry and life science.But,there still exist many unsolved challenges awaiting solutions.The key to those challenges is how to measure the trace and even ultra-trace substances from limited living samples.The complex life system and diversified molecular interactions set higher requirements for in-vivo and in-situ testing technology,especially because endogenous substances like hormones can move in a living body and can be transported from the part where a life is born to the action part.Therefore,developing a fast,high through-put and full-analysis technology,which can be connected to modern analytical instruments,is the key burning issue of the in-vivo and in-situ testing.The point of the in-vivo and in-situ testing lies is in the research and development of the pretreatment technology of innovative samples.The liquid phase microextraction(LPME)has been widely applied thanks to the low use of solvent,high enrichment factor,rapid and green process.Among them,the selection of organic solvents is a crucial factor in improving the LPME efficiency,while the physical and chemical properties of the liquid phase will restrict the LPME application in in-vivo testing.The substances confined in nanoscale space show the strikingly different nature from their phases.Will the nanoconfined overcome the weak stability,poor biocompatibility and easy diffusion arisen from the liquid phase itself? This is a pioneering idea,but there has been no report on the “nanoconfined microextraction” at home and abroad so far.The main research and results of this paper are as follows:1.With the well-known flexible carbon fiber material as the substrate,the chemical vapor deposition(CVD)and the dip coating methods were adopted to modify the carbon fiber from its surface morphology and functional group.The carbon nanofibers/carbon fibers(CNFs/CFs)and the chitosan-coated carbon fibers(CCFs)were successfully prepared.Then,the feasibility of nanoconfined solvent behavior was preliminarily explored.The CVD parameters were optimized to provide a theoretical foundation for the precise control of the CNFs/CFs morphology.2.The thermodynamic and kinetic experiments were conducted to have an initial research on the technological mechanism of liquid phase nanoextraction(LPNE).The research of the kinetic model showed that the extraction process follows the pseudosecond-order kinetics and can be divided into three stages: LPNE,the synergic extraction of LPNE and solid phase microextraction(SPME),and SPME.3.By dint of the broad spectrum,diverse combination forms and easy replacement of nanoconfined solvents,different polar compounds(12 kinds of acid-base phytohormones,7 kinds of ginsenosides and 13 kinds of pesticide residues)were analyzed.It was easy and simple to replace the nanoconfined solvents to achieve the selective extraction or comprehensive analysis.Organic water-soluble solvents,such as acetonitrile,methanol and ethanol,were applied to the analysis of the phytohormones,ginsenosides and other strong and moderate polar compounds.This broke the chains of LPME technology in the mutual-soluble two-phase extraction.4.Pencil CCFs-SPME combined with "fiber" in situ derivatization method were used to determine the acid phytohormones in wheat samples.The in-situ derivatization of “fiber” can effectively reduce the by-products,and show great advantages in in-situ,sensitive and selective extraction,in addition to few and simple steps of analysis and determination.5.The umbrella-type device and needle-tip device were designed to “activate” the in-vivo and in-situ analysis of static phytohormones,which were applicable for the analysis of semi-fluid or juicy-rich plant samples.The in-vivo and in-situ analysis of 12acid-base phytohormones was completed within 1–2.5 minute.The data accuracy of phytohormones was verified through the umbrella-type liquid phase nanoextractor and the needle-tip liquid phase nanoextractor,after comparing with the results through the Qu ECh ERS,MS-LLLME and pencil-lead CCFs-SPME methods.With the carbon nanofibers/carbon fiber as the substrate,the nanoconfined liquid phase nanoextraction technology described in this paper has achieved the nanoextraction of liquid phase extraction technology.The LPNE technology is strong in simple operation,high stability and high extraction efficiency,besides the advantages of both SPME and the LPME.Its original phase separation technology breaks new ground in mutual-soluble two-phase extraction.The selective extraction or comprehensive analysis of strong,moderate and low polar compounds was realized by leveraging the wide spectrum,diverse combination forms and easy replacement of the nanoconfined solvent.Combining with the umbrella-type device and needle-tip device,the in-vivo and in-situ analysis of 12 acid-base phytohormones was finished,offering a new technology for studying the multi-molecular network in life activities.The in-situ and comprehensive analysis of phytohormones is only a representative application of LPNE,and its development should not be limited.For example,the SPME,the last part of this paper,also has potential applications and can be defined as an array synergistic liquid-solid phase extraction technology.In the application promotion research,the LPNE part can be regarded as a “docker”,and the SPME part a “storage room”.The joint efforts of LPNE and SPME will set a new trend in pollutant treatment and control.