| The combination of various functional modes within a flexible,intelligent system to achieve efficient separations is an important trend among recent developments in the field of high-performance liquid chromatography.Based on the research objectives of the"National Key Scientific Instrument and Equipment Development Projects" by the Ministry of Science and Technology in the "12th Five-Year Plan",various components of an HPLC system were systematically redesigned,including the high pressure pump,the detector,the stationary phase for chromatographic column,and the system control and interface technology.The existing technologies were improved,compacted,and supplemented with new modules.Appropriate combinations were made to improve functionality,thereby greatly broadening the scope of application.A phase transformation-driven micro-infusion pump was designed using n-tetradecanol as the energy storage material.The maximum pressure limit was 83 MPa.A new type of infusion pump with a direct drive motor and a pressure limit over 100MPa was also designed.Stable fluid output occurs from 0 to 1000 nL/min,with a standards analysis RSD value(n=5)better than 1%.Several high-pressure gradient mixers were designed,and the effects on their outputs were investigated.It was confirmed that the ball scheme and the cylindrical scheme have better mixing effects by the fluid dynamics simulation,Reynolds coefficient calculation,and chromatographic behavior evaluation.A low-pressure gradient distribution method based on heart-cutting was designed,with lower demand for accuracy of mechanical debugging.Good gradient distribution accuracy was obtained even with inaccurate positioning of the cam.A high-resolution chromatographic optical detection system was designed based on the principle of off-axis aspheric reflection.The optical imaging and air channel simulation were performed using Zemax and Flow Simulation.The optical resolution of the 1024 array was 0.8nm.The miniature single-wavelength detector was designed with a 260-nm LED light source and was only 65mm×45mm×60mm in size;its basic performance indicators met the requirements of conventional detectors.Fluorescence brightener OB was used as a probe to evaluate the performance of a confocal LED-induced fluorescence detector based on a 365-nm LED light source.The linear range was 3 orders of magnitude,and the detection limit was 0.14fmol.A new integrated fraction collector-autosampler interface was designed utilizing a multi-functional valve and dual-circuit technology in order to achieve multiple functions for sample collection and sample injection.Four aromatic compounds were used to analyse the collection purity,and five standard proteins were used to evaluate the collection-selective re-separation character.Both sets of experiments yielded excellent results.Ethernet was used as the communication interface of the system,and attributes such as port filtering,instrument serial number filtering,protocol framework,and check digit filtering were added to the traditional UDP protocol to ensure the accuracy of data transmission in complex systems.Based on these parameters,a multi-functional liquid chromatography system was constructed,successfully incorporating an integrated control through a dedicated chromatographic workstation,thereby greatly improving the degree of automation and stability of the system.Using the "one-pot method",octadecyltrichlorosilane and 3-mercaptopropyltrimethoxysilane were bonded to the surface of silica gel,and further oxidation was performed to obtain a C18-sulfonate doubly-modified stationary phase.Using the prepared stationary phase,five alkylbenzene compounds were separated in the reversed phase mode,and three nucleosides were separated in the hydrophilic mode.Excellent results were also obtained for the separation of bovine serum albumin hydrolysate,which demonstrated that the stationary phase provided multiple interaction sites while offering multiple separation mechanisms.A triazine-amide composite-modified stationary phase was successfully prepared by a 4-step continuous reaction.The separation results of the basic aniline and pyridine compounds revealed excellent chromatographic performance,effectively avoiding the common problem of peak tailing during separation of basic compounds on a conventional C18 column.The novel core-shell phases with radial pore-shell structures of 1.9?m and2.6?m were characterized,and the column packing processes were investigated.The number of column theoretical plates was 177,100/m.The multi-functional liquid chromatography system was used to carry out relevant research on the detection of toxic substances in Chinese native medicine ingredients,food,and environmental samples and in the application of proteomics.In the diode array detection mode,a variety of methods for the detection of illegal additives and active ingredients in Chinese herbal medicines were developed,and spectral-assisted qualitative functions were used to avoid false positive results.An analytical method for the direct extraction of benzo(a)pyrene from feed was developed using the LED-induced fluorescence detection mode.This method reduced pretreatment time by 90%and reduced reagent consumption by 95%compared to the traditional method.Using the rapid separation model of core-shell packing,analysis methods for 13 non-methane organic gases found in automotive exhaust were developed,thus reducing the analysis time by more than half.Using the AD expansion mode coupled with fluorescence detection technology,an analytical method for the detection of benzo(a)pyrene in different substrates was also developed.Combining both photochemical and post-column derivatization systems,methods for detection of aflatoxins in Chinese medicines,grains and oils,and carbamate pesticides in fruits have been developed.An integrated two-dimensional liquid chromatographic separation system was constructed with an integrated fraction collector-autosampler interface.Using a bovine serum albumin digestion product as the evaluation material,the peak capacity of the system reached 4752.Yeast protein was fully analysed by taking advantage of the multi-functional integration of the system.Two-dimensional separation,online digestion,enrichment,desalination of proteins and the micro/nano-fast separation of enzymatic peptides with mass spectrometry tests and other operations were completed in sequence in a highly efficient manner.These tests indicated that the integrated system performed adequately and highlighted the powerful advantages in the analysis of complex biological samples. |
PDF Full Text Request