【作者】 王玉娇；

【导师】 熊博；

【作者基本信息】 华中师范大学 ， 分析化学， 2015， 硕士

【摘要】 微流控芯片具有耗样量少的特点,在其上可集成各种样品操作(如混合、过滤、分离等),在蛋白质组学、单细胞分析等研究领域有着广泛的运用。质谱灵敏度高、定性能力强,特别适合用于微流控芯片的检测,因而相关芯片-质谱联用方法在基础研究中受到了广泛的关注。在所有离子源中,电喷雾离子源可实现对液态样品的离子化,且可在大气压条件下进行操作(无需真空),因而运用相对广泛。常规的ESI离子源只能对较大流速液流实现离子化,无法实现对纳升级液流的分析检测。现有提高样品利用率的研究大多侧重于制备小尺寸喷雾口,但是此类接口大多数难以制作且重现性不好。有鉴于此,本研究基于微流控三维聚焦技术对电喷雾泰勒锥中样品离子分布的调控,达到抑制电喷雾进样损耗的目的。此外,通过在芯片中集成标准参比质量校准离子,达到提高检测方法分辨率的目标,最终建立一种可实现纳升级液流的高分辨率微流控芯片-ESI-MS方法。本实验主要研究如下:1.本研究通过对芯片的合理设计,基于聚焦液对样品进行三维聚焦,将样品微流聚焦至整体液流剖面中心区域,从而实现对泰勒锥电喷雾中样品离子扩散的抑制。本研究还使用该三维聚焦ESI源对实际样品罗丹明B和利血平进行了质谱检测,实验表明该三维聚焦芯片的确可以达到降低样品消耗的目的。2.为基于前述的三维聚焦芯片实现质谱检测的高分辨率,我们将高分辨质谱的参比溶液充当实验中的水平和垂直聚焦液,并在溶液周围刻蚀氮气尾吹通道,提升样品的雾化强度,进而实现对待测样品的高分辨率检测。通过芯片ESI源对实际样品罗丹明B和利血平的质谱检测,表明在样品喷雾中加入高分辨质谱参比溶液喷雾的确可以达到高分辨的目的。3.由于本研究采用聚二甲基硅氧烷作为制备芯片的材料,在提高芯片雾化强度以后,芯片内的寡聚单体对样品检测影响也大幅度提高。实验通过在芯片内部涂渍十八烷基三氯硅烷,将芯片内的寡聚单体与流经通道的有机溶剂分开,实现了降低由于芯片表面寡聚单体对芯片-质谱联用检测信号的干扰。综上所述,本研究建立了一种基于三维聚焦技术的微流控芯片-NANO-ESI-MS联用方法,该方法具有检测分辨率高、适配样品流速低的优势,可为后续基于芯片平台对样品中微量组分在线结构分析打下良好的基础。更多还原

【Abstract】 Microfluidic chip own low sample consumption and the probability to integrate various samples treatment(such as mixing,filtration,separate,etc.).There for it has been widely used in the research of proteomics,single cell analysis and so on.Mass spectrometry(MS)own high sensitivity and powerful qualitative.Because of which it has been widely reported to be a good detector of microfluidic chip.Coupling microfluidic chip with MS has attracted interest.In all kinds of ionization resource,ESI source could be realized ionization for samples in liquid,and it is capable with normal air pressure(vacuum is not strictly required).There for it had been widely utilized.Conventional ESI resource could only be coupled with those sample flow which own a suitable flow rate such as several microliters per minute,and it is could not realize the ionization for nano sample flow.In recent reports,most usual strategy was focused on the fabrication for spray emitters which own a very small size,while those interfaces are difficult to be made,as well as its repeatability.Under these kinds of situations,our research utilized microfluidic three dimension hydrodynamic focusing strategy to inhibit the sample expansion in the ESI spray,and modulated the distribution of sample ions in the pattern.Moreover,MS reference solution was integrated into the sample flow to improve the resolution for the proposed MS strategy.The final aim for over research was to realize an ESI ionization for nano sample flow with a decent MS resolution.Generally,our research was reported as following:1.Based on the reasonable design for microfluidic chip,focusing solution was used to focus the sample flow in 3D.Under these kinds of treatments,the sample flow was controlled to be in the center of the general flow puffier,based on which the sample ion expansion in the taylor cone was highly inhibited.In addition,the proposed 3D ESI resource chip was used to determine rhodamine B and reserpine.Experimental result indicated that 3D hydrodynamic focusing in chip was indeed capable of low sample consumption.2.In order to realized the high resolution for MS,the reference solution in standard high resolution MS was used to take place of conventional hydrodynamic focusing solution in both vertical and horizontal direction.More over nitrogen flow rate was integrate into the chip in four directions to improve the ionization efficience.The ESI resource based on the microfluidic chips which own both MS reference function and nitrogen flow function was used to determine rhodamine B and reserpine.It was shown that the proposed microfluidic chip could be realized a high MS resolution determinations,and its sensitivity as well as its ionization efficience was rather satisfactory.3.PDMS was used to fabricate the proposed chip,and the oligomers in the chip would be dissolution in the sample flow,because of which the background ions in MS determination would be rather high.Our strategy was to use octadecyltrichlorosilane to coat channels in the chip,based on which organic solution was prevented from the PDMS.Generally oligomers in PDMS would not indicate strong interference in the proposed combination for microfluidic chip and MS.In a sum,our research achieved a strategy to couple focusing chip and MS,which was based on 3D hydrodynamic focusing.This kind of method owns high resolution and it is suitable to realize the excitation for low sample flow in nano skill.It would be a satisfactory theoretical and experimental foundation for further research.更多还原