Design And Application Of Mobility Electrophoresis-mass Spectrometry Device

Mass spectrometry(MS)is a widel y applied detection technology which can provide the mass to charge ratio and str uctural information of an ion.It gathers lots of advantages such as high sensitivity,suitable for qualitative and quantitative anal ysis and is prone to miniaturization.The analysis of complex samples is a challenge in the field of analytical chemistry.With matrix effect,the low abundance components in real sample are hardl y to be detected without pretreating or separating process.However,a small volume sample or low concentration sample is hard to withstand complex separation processes,hence a simplified and efficient separation method is needed.With separation effect,liquid chromatograph y(LC)and capillary electrophoresis(CE)are coupled with mass spectrometry for complex sample anal ysis in liquid phase.However,LC anal ysis is time consuming an d in need of large amounts of reagents and samples.Meanwhile,CE has a poor compatibilit y and stability with MS.As a result,developing a novel separation and anal ysis method with the characteristics of convenient equipment,tin y reagents and samples consumption,rapid anal ysis,MS-compatible,accurate identification of complex samples b y multidimensional information is crucial.Moreover,a suitable ionization method is also essential for MS anal ysis.The following application of electrospray ionization(ESI)has accelerated the development of online biomolecule anal ysis.However,during the ESI process,there exists a charge competition effect.Accordingly,when anal yzing complex samples,some anal ytes might be suppressed.Our preliminary work,electro-kinetic assisted electrospray ionization,have been down to reduce charge competition and increase biomolecule detection sensitivit y.In ME,a fast and MS-compatible separation method with setup and experiment improvements for better separation has been pr oposed and characterized.This paper mainl y includes 4 parts :(1)In the review section,the related knowledge of mass spectrometry,coupling techniques for complex samples separation,such as chromatograph y-mass spectrometry,capillary electrophoresis-mass spectrometry are introd uc-ed.Finall y,the ion source interface used in biological anal ysis of liquid phase is introduced.(2)Theoretical derivation and numerical simulation of mobilit y electrophoresis have been carried out and the mechanism of separation is thoroughl y studi ed.Mobilit y electrophoresis is a kind of as a separation process related to the particle size and charged state in liquid phase.The anal ytes are taken forward together mainly b y the pump pressure,separated for different particle sizes and particle charge s b y the applied reverse high voltage and eventuall y sprayed b y a nano-ES I emitter for MS anal ysis.Besides,several main influencing factors were anal yzed b y simulation and verified b y capillary zone electrophoresis experiments.(3)We designed and optimized a discrete and a high-throughout electrophoresis device on the basis of the theory of mobilit y electrophoresis.A serious of parameters optimization were carried out to achieve a better separation result.The optimization mainly fell on the separation buffer,the flow rate of the s yringe pump and the reverse high voltage through the separation of two peptides.We used the 70%(w:w)acetonitrile(0.1%(w:w)formic acid was added)as the separation buffer,-7 kV at 20?l/h flow rate as the basic separation condition.(4)A series of experiments were carried out to show its separation abilities and application prospect.First of all,we selected a pair of isomers and they were separated well.Moreover,we separated a mixture of six compounds(one amino acid,two peptides,three proteins).Therefore,while there exists the charge competition effect,the method can be helpful for low volume complex substances anal ysis and there is a great potential for rapid cell anal ysis.Finally,it was found that compared w ith the nano-liquid chromatogragh y method,we can obtain similar coverage rate with less time in BSA enz ymatic h yd rol ysates anal ysis.There exists a great potential for realizing rapid high-throughout proteomic anal ysis.