便携式微型液相色谱仪的研制

Development of a portable micro-liquid chromatograph

该工作报道了一种自行设计研制的便携式微型液相色谱仪(portable micro liquid chromatograph,p-μLC)。p-μLC集成了二元大推力注射泵作为流动相驱动装置、毛细管整体柱为分离介质和紫外-可见/荧光两用流通池为在线检测单元。自行设计研制的二元大推力注射泵可以实现等度/梯度洗脱和流动相再装填功能,可控流速范围在0.025μL/min到5.6 mL/min之间;自制的甲基丙烯酸酯C-18有机聚合物毛细管整体微柱可实现自有机小分子至生物大分子的分离;自行研制的光纤式紫外-可见/荧光两用流通池,可以通过光纤导入来自光源的紫外光和可见光,并采集透射光和与入射光反方向射出的荧光信号,流通池内使用自聚焦透镜和全反射光导毛细管等器件提高通光效率和吸收光程;两用流通池通过光纤分别连接由大功率发光二极管/脉冲氙灯光源和微型光栅光谱仪所组成的检测装置进行在线吸收和荧光光谱检测,检测波长范围为220~700 nm。p-μLC采用整体手提箱式结构,流路模块、检测模块等位于下主箱体中,采集、控制模块等位于上盖中,全重不超过8 kg。仪器由装载了自编控制采集软件的内置平板电脑进行控制和数据采集。使用自行制备的甲基丙烯酸酯C-18有机聚合物毛细管整体柱,在等度洗脱模式下,在p-μLC上分离了烷基苯化合物混合样品,其分离检测效果可以与商品化大型HPLC仪器相媲美。

Portable analytical instruments find extensive application in on-site examination because of their significant advantages:these instruments are convenient and easy-to-carry,leading to high time-effectiveness,and involve low reagent consumption.We report a portable micro-liquid chromatograph(p-μLC)that was designed and fabricated in our laboratory.The p-μLC integrates homemade dual large-thrust syringe pumps for delivering the mobile phase,a capillary polymer monolithic column as the stationary phase for the separation of the target analytes,and a specially designed dual-functional optical-fiber microflow-cell for online detection.The dual-thrust syringe pumps can realize isocratic and/or gradient elution as well as reloading of the mobile phase,with flow rates ranging from 0.025μL/min to 5.6 mL/min and the maximum working pressure of 4.5 MPa.The polymethacrylate based C-18 monolithic column facilitates the separation of small organic molecules and biomacromolecules.A homemade high-power light emission diode(LED)light source and a modified xenon flash lamp are assembled as the light source module.The dual-functional detector consists of an optical fiber microflow-cell with a self-focusing lens and a light-guiding capillary,light source module,and a small-sized grating spectrometer with an output wavelength range of 400-680 nm for the LED light source and 220-700 nm for the xenon flash lamp,enabling online detection of the absorption and fluorescence spectra of the analytes from 220 to 700 nm.A bifurcated optical fiber bundle is prepared and used to connect the light source,microflow-cell,and grating spectrometer so that the incident light leading-in and the fluorescence/scatting light leading-out can be realized simultaneously.The junction end of the bifurcated optical fiber bundles connects to one end of the light path of the microflow-cell,and a straight-through optical fiber connects another end of the microflow-cell.In the UV-Vis absorption mode,the straight-through optical fiber reads out the transmitted light,while in the fluorescence mode,the excitation light beam from the light source irradiates the sample solution in the flow-cell via one branch of the bifurcated optic fiber bundles.The fluorescence leading-out via the other branch of the bifurcated optical fiber bundles in the opposite direction of the excitation light beam is read out by the spectrometer.All the large-thrust syringe pumps and flow-path,capillary monolithic column,and optical fiber mediated flow-cell detection as well as controlling modules are installed in a suitcase with a total weight of less than 8 kg.The p-μLC is powered by DC 12V 3A or 18650 lithium battery pack and controlled by a panel computer with a custom-built windows-based chromatography workstation software for data acquisition.When using the home-made polymethacrylate based C-18 monolithic capillary column(530μm ID×200 mm in length),the mixed alkylbenzenes can be separated and detected in an isocratic elution mode.The separation efficiency is comparable to that obtained with a commercially available HPLC.