Development of Ultranarrow-Bore Open Tubular High Efficiency Liquid Chromatography

Chromatography theory shows that when the inner diameter of the chromatography column is very narrow(e.g.,1—2μm),the maximum efficiency will be produced in liquid chromatography.In addition,the increasing demand for ultrasmall volume sample analysis has produced the trend of narrowing the diameter of the liquid chromatography column.Experiments have verified that ultranarrow-bore open tubular liquid chromatography(i.d.≤2μm)has the advantages of small sample requirement and high separation efficiency.However,there also exist huge challenges along with such obvious advantages.This review summarizes the efforts made by our research group and other research groups to develop this field.We hope that in the near future,ultranarrow bore open-tube liquid chromatography can be successfully and maturely applied to the application of analytes with ultrasmall size and volume such as single-cell and even subcellular organelles omics research.     

On-line parallel reversed phase two-dimensional liquid chromatography for high-throughput analysis of complex proteomic samples

A comprehensive two-dimensional liquid chromatographic system (2D SCX/RP) is con- structed with a 10-port-2-way valve using strong cation exchange chromatography (Hypersil SCX, 100 mm×4.6 mm I.D.) followed by reversed phase chromatography (Hypersil BDS C18, 15 mm×4.6 mm I.D.) to separate the complex peptides from globin peptic hydrolysate. After the sample was loaded on the SCX column, the phosphate buffer (pH 4.0) was used to elute the peptides. Then, elutes flowed through the interface and the peptides focused on the head of the trapping columns (Hypersil BDS C18, 15 mm×4.6 mm I.D.) but salt passed into the waste. After the valve was switched, the samples were flushed with a backward flow into the RP analytical column. The peptides on the SCX were eluted with 12 discontinuous steps linearly increasing salt concentrations. The peptides enriched on the trapping column were desalted and separated by the RP columns. The resolution and the resolved peaks of the 2D SCX/RP system were greatly increased and the total peak capacity reached as high as 2280.     

Styrene epoxidation with hydrogen peroxide over calcium oxide catalysts prepared from various precursors

A series of CaO samples were prepared by calcination of commercially available and synthesis of calcium salt precursors such as calcium acetate,carbonate,hydroxide and oxalate etc.CaO samples were found to be effective for the epoxidation of styrene using hydrogen peroxide as an oxidant in the presence of acetonitrile.To determine the influence of the physicochemical properties and surface basicity on the catalytic activity,the prepared CaO samples were characterized using thermogravimetry(TG),X-ray diffraction(XRD),scanning electron microscopy(SEM),N2-adsorption and temperature-programmed desorption of CO2(CO2-TPD).The results indicate that the amounts of very strong basic sites and high basicity strength on CaO sample are key factors for its excellent catalytic performance.In contrast,the surface area,porosity and the surface structure of CaO sample have a relatively minor effect on the catalytic activity.CaO sample,obtained by the decomposition of Ca(OH)2,prepared by precipitating calcium nitrate with sodium hydroxide in ethylene glycol solution,exhibits the highest amount of very strong basic sites and stronger strength of basic sites,and therefore it catalyses the epoxidation of styrene with the highest rate among the tested CaO samples.Under the selected reaction conditions,the selectivity of 97.5% to styrene oxide at a conversion in excess of 99% could be obtained.     

PREPARATION AND EVALUATION OF SMALLBORE REVERSED PHASE HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC COLUMN

A smallbore chemically bonded alkyl stationary phase column of 2 mm I. D.(inner diameter) and 15 cm in length having an efficiency of 6400—7600 theoretical plates has been developed. The column officicncy is nearly the same as that of routine analytical column of 4.6—5.0 mm I. D. The amount of cluant used for the smallbore column, however, is less than about one fifth that for the ordinary columns.Using the reaction of monochlorosilane with 5 μm accumulated silica bead produced in Qingdao Ocean Chemical Factory instead of trichlorosilane and irregular silica gel, we have. prepared a nonpolar chemically bonded phase packing which has a higher carbon content and more obvious hydrophobicity. Moreover, the reproducibility of the preparation is better.The equipment and assembly necessary for getting high efficiency with the smallbore column are discussed briefly. Using Model SW-1 smallbore column HPLC instrument developed in the institute with the Model K-1 column fittings and injector, the detector with     

Electrospray Lonization Fourier Transform Ion Cyclotron Resonance Mass Spectrometric Study on Sodium Azide Cluster Ions

Sodium azide has rarely been studied in gas phase or in the form of cluster ions and as a model of solid energetic substances and inorganic azide salt was ionized by electrospray ionization (ESI) and studied by high resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry (MS) systematically. This paper highlights the effects of experimental conditions on the formation of salt cluster and the collision activation dissociation pathways of cluster ions to develop a microscopic understanding of inorganic azide salt clusters.     

Determination of D- and L-amino acids in biological samples by two-dimensional column liquid chromatography

Summary A two-dimensional, column liquid chromatographic system is used for the determination of the D- and L-enantiomers of amino acids in biological samples. Separation of the amino acids is first on ion-exchange column by gradient elution with a sodium citrate-sodium chloride buffer. Enantioseparation is by subsequent injection of 3 μl heart-cuts of the individual amino acids onto a second column with a chiral crown ether stationary phase. Finally, fluorescence detection is after post-column labelling of the amino acids using ano-phthalaldehyde-2-mercaptoethanol reagent solution. The high separation power and selectivity of the system allow processing of complex samples with hardly any additional treatment and the determination of small quantities of D-amino acids in the presence of excess L-form. Applicability of the system is illustrated by the determination of D- and L-aspartate, serine, glutamate and alanine in various complex biological samples, such as protein hydrolysates, urine and biotechnological and food samples. Data are given on detectability, repeatability and linearity.     

Triptycene-derived heterocalixarene: A new type of macrocycle-based stationary phases for gas chromatography

This work reports the investigation of a new triptycene-derived oxacalixarene(TDOC) as the stationary phase for gas chromatography(GC) with high-resolution performance for a wide range of analytes and isomers.The TDOC scaffold is composed of triptycene and 1,8-naphthyridine moieties,inherently differing from the conventional calixarenes in structures and properties.As a result,the TDOC column exhibited outstanding column efficiency of 5679 plates/m by n-dodecane at 120℃.It showed advantageous performance for separations of the mixtures with various analytes and achieved high resolution of diverse isomers(skeletal,positional and cis-/trans-isomers) from apolar to polar nature.Moreover,the TDOC column exhibited high thermal stability up to 310℃.To date,the TDOC-based materials have not been reported in chromatography.This work demonstrates the good potential of the triptycene-derived heterocalixarenes as a new class of stationary phases for chromatographic analyses.     

亲水作用色谱柱与阳离子交换树脂柱结合分离无机离子（英文）

A combination of hydrophilic interaction chromatographic(HILIC) column and a weakly acidic cation-exchange resin(WCX) column was used for simultaneous separation of inorganic anions and cations by ion chromatography(IC).Firstly,the capability of HILIC column for the separation of analyte ions was evaluated under acidic eluent conditions.The columns used were SeQuant ZIC-HILIC(ZIC-HILIC) with a sulfobetaine-zwitterion stationary phase(ZIC-HILIC) and Acclaim HILIC-10 with a diol stationary phase(HILIC-10).When using tartaric acid as the eluent,the HILIC columns indicated strong retentions for anions,based on ion-pair interaction.Especially,HILIC-10 could strongly retain anions compared with ZIC-HILIC.The selectivity for analyte anions of HILIC-10 with 5 mmol/L tartaric acid eluent was in the order of I-> NO-3 > Br-> Cl-> H2PO-4.However,since HILIC-10 could not separate analyte cations,a WCX column(TSKgel Super IC-A/C) was connected after the HILIC column in series.The combination column system of HILIC and WCX columns could successfully separate ten ions(Na+,NH+4,K+,Mg2+,Ca2+,H2PO-4,Cl-,Br-,NO-3 and I-) with elution of 4 mmol/L tartaric acid plus 8 mmol/L 18-crown-6.The relative standard deviations(RSDs) of analyte ions by the system were in the ranges of 0.02%-0.05% in retention times and 0.18%-5.3% in peak areas through three-time successive injections.The limits of detection at signal-to-noise ratio of 3 were 0.24-0.30 μmol/L for the cations and 0.31-1.2 μmol/L for the anions.This system was applied for the simultaneous determination of the cations and the anions in a vegetable juice sample with satisfactory results.     

Microwaves spark emission spectroscopy for the analysis of cations:A simple form of atomic emission spectroscopy

A novel method for the cation analysis was investigated.The analysis is based on the sparking of the salts of metals in a microwave oven after placing in a graphite cell.The graphite cell absorbs microwaves and produces high temperature which converts the salt into light emitting species.The colour of light was found to dependent on the nature of cation,however,the intensity of the emitted light was found to be depending upon the form and shape of the graphite assembly in addition to the concentration of the salt.This communication presents explanation for all these observations and for the systematic and quantitative analysis using microwave spark emission technique.     

Separation and Purification of Glufosinate Through Combination of an Electrodialysis Membrane and a Macroporous Adsorption Resin

Glufosinate is a nonselective organophosphorus herbicide with low toxicity and high efficiency that is widely used in forestry, agriculture and other industries. In the process of manufacturing glufosinate, large amounts of ammonium chloride and coloured organic impurities are generated. Because of its high solubility in water, separation of glufosinate from inorganic salts is extremely difficult. Hence, a co-separation method combining an electrodialysis membrane and a macroporous adsorption resin was developed to obtain glufosinate with higlier purity. For the electrodialysis process, a glufosinate reaction solution was placed in a dilute chamber and desalinated. The concentration of inorganic salts in the resultant glufosinate aqueous solution was only 0.99 g/L under the optimal conditions of an operating voltage and a volume ratio of 9 V and 1:1, respectively. For the macroporous resin adsorption/desorption process, the sample solution treated by electrodialysis was pumped into the resin-filled column, which was eluted to obtain the eluent when the adsorption reached equilibrium. Consequently, nearly all the coloured organic impurities were removed under the optimal conditions, in which the resin type, pH value, flow rate, glufosinate concentration, temperature, ratio of ethanol and volume of eluent were LX-300C,3,0.5 mL·cm^2·min^-1,20 mg/mL,25℃, 50% and 400 mL, respectively. After the electrodialysis and adsorption/desorption process, the purity of the glufosinate was increased to 95.14%, and its recovery rate was as high as 98%. The advantages of this process included its ease of operation, environmental friendliness and low cost, which provided strong potential for its use in industrial applications.     

用于合成新型1,3,5-三芳基吡唑啉衍生物的磷钨酸铯盐的纳米塑形、模板合成及结构研究(英文)

The elimination of the silica matrix of composites by HF occurred by a two-step reaction deposition of a Cs2.5H0.5PW12O40(CsHPW) salt nanocrystal.We used 2D hexagonal SBA-15 silica as a template for the nanofabrication of CsHPW nanoparticles.Nanocast CsHPW materials are stable against leaching and colloidization in polar solvents.The catalytic performance of the nanocast CsHPW materi-als exceeded that of bulk Cs2.5H0.5PW12O40,which is the most active among the acidic HPW salts.A series of novel 1,3,5-triaryl-pyrazoline derivatives were synthesized by the reaction between chalcone and phenylhydrazine in high yield in the presence of CsHPW salt nanocrystals.     

EXAMINATION OF THE SURFACE FREE ENERGY AND ACID-BASE PROPERTIES OF CELLULOSE BY THE COLUMN WICKING TECHNIQUE AND THE CRITICAL PACKING HEIGHT/DENSITY

INTRODUCTIONThe wicking technique has been used to determine the surface energy components of solids[1-7]. Generally, thereare two wicking processes in practice, i.e. thin layer wicking and column wicking. A comparison of the twowicking techniques made by van Oss et al.[2], shows that column wicking has a problem of showing differentpacking density due to some kinds of powder materials, i.e. clay can not give good repacking reproducibility[2].But thin layer wicking has a problem in sample…     

Determination of the impurity of isopentylamine hydrochloride in the intermediate of bortezomib by HPLC with pre-column derivatizationEI北大核心CSCD

A method was developed for the simultaneous determination of R-pinacol-1-amino-3-methylbutylborate hydrochloride and isopentylamine hydrochloride by pre-column derivatization high performance liquid chromatography HPLC with dichloromethane as solventtriethylamine as acid binding agent and benzoyl chloride as derivative reagent. R-pinacol-1-amino-3-methylbutylborate hydrochloride and isopentylamine hydrochloride reacted with derivatization reagent in an ice bath for 10 min. The derivatives were qualitatively determined by HPLC-mass spectrometryHPLC-MS. HPLC was performed on an AgelaVenusil MP C18 2column using methanol-water 7030V/Vas mobile phase. The flow rate was 1.0 mL/minthe detection wavelength was 236 nm and the column temperature was 35 . The UV absorption produced after derivatizationwhich could be detected by HPLC with good specificity. Isopentylamine hydrochloride derivative showed an excellent linearity in the range of 0.075-30 μµg/mLwith the limit of quantification and the limit of detectionLODof 0.075 and 0.030 μµg/mLrespectively. And the S/N of the LOQ and the LOD were 44.6 and 7.8respectively. The average recoveries were 97.7%-104.0% with the RSD of 2.9%. The method is suitable for the determination of isoamylamine hydrochloride and has significant reference value for the determination of other amine salt without UV absorption. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

PRELIMINARY RESEARCH ON CLAY MINERALS IN SALT LAKE SEDIMENTS OF CHINA AND ITS SIGNIFICANCE

Most of the clay minerals in salt lakes of China are characterized by illite-chlorite as-semblage, with a minor amount of montmorillonite and kaolinite and so on. There are ob-vious differences between mineral assemblages, relative contents and chemical compositionof clay minerals in salt lakes of different areas and in different sedimentary stages. Clayminerals in these salt lakes are basically allogenic, but transitional origin may also exist.The characteristics of clay minerals in salt lakes are controlled by the arid climatic zone ofChina and the different material supplies of salt lakes. With the data taken from clay miner-al study, the author discusses the relation of sedimentary environment of salt lakes, theregularities of immigration and enrichment of mineralization elements.     

Atomic absorption spectrometric determination of Fe(III) and Cr(III) in various samples after preconcentration by solid-phase extraction with pyridine-2-carbaldehyde thiosemicarbazone

An atomic absorption spectrometric method for the determination of Fe(III) and Cr(III) after solid-phase extraction of their Schiff-base chelates by a column procedure with Amberlite XAD-4 was developed. A Schiff base, pyridine-2-carbaldehyde thiosemicarbazone (PCTSC), was synthesized and used as a chromogenic reagent for solid-phase extraction of Fe(III) and Cr(III) ions in the column procedure. The influence of various analytical parameters including the amount of solid phase, pH, type of elution solution, volume of sample solution, and flow rate of sample solution on the extraction efficiency of analytes were investigated. The recoveries of Fe(III) and Cr(III) were 99 ± 1 and 98 ± 2%, respectively, at the 95% confidence level under the optimum conditions. Fe(III) and Cr(III) were preconcentrated up to 25-fold. The limit of detection of Fe(III) and Cr(III) are 4.1 and 3.72 μg/L, respectively. The proposed method was applied to the determination of these metal ions in tap water, river water, Atatürk Dam water, and alloy samples. The relative standard deviation and the relative error are lower than 6%. The text was submitted by the authors in English.     

剖析液相色谱柱技术的复杂状况(英文)

 Column packings continue to evolve as the needs of users for high efficiency, high resolution and highly sensitive high performance liquid chromatographic (HPLC) analysis drive further developments. In comparing and contrasting modern HPLC columns technologies, diameters of column packings and particle materials are covered. Some products and applications of modern HPLC columns are provided. Future directions in packing developments are predicted in this introductory article.     

Thermodynamic Analysis and Experimental Investigation into Nonflame Combustion Technology（NFCT） with Thermal Cyclic Carrier

The utilization of fossil fuels causes serious negative impacts on the environment and human life. To mitigate greenhouse gases and other pollutants, a novel combustion process-the nonflame combustion technology with a thermal cyclic carrier of molten salt is introduced. In this technology, a whole combustion is divided into two steps, i.e. , the section of producing oxide and the section of combustion. In the first step, oxygen is separated from air, and pure N2 is simultaneously formed which is easily recovered. In the other step, the fuels react with lattice oxygen in the oxides formed in the first step, and at the same time, thermal energy, CO2 and H2O vapor are produced. It is noted that the CO2 is easily separated from water vapor and ultimately captured. Theoretically, there are no environmental-unfriendly gases such as CO2, NOx and SO2 discharged in the whole combustion process. Some metal oxides scattered into molten salts play the roles of oxygen carriers in the combustion system, and they can constantly charge and discharge oxygen element from air to fuels during the combustion process. A nonflame combustion system with Li2CO3 K2CO3 Na2SO4 as the molten salt system, CH4 as the fuel and CuO as the catalyst was experimentally investigated. The experimental resuits show that the combustion process proceeded as it was theoretically analyzed, and CO2 with a high volume fraction of 77.0M--95.0M and N2 with a high volume fraction of 91.9%-99.3% were obtained. The high concentration of CO2 is favorable for capturing and storing subsequently. Therefore, the potential of reducing CO2 emissions of this nonflame combustion technology is huge.     

Analysis of chloramphenicol in honey by on-line pretreatment liquid chromatography-tandem mass spectrometry

Chloramphenicol is an antibiotic and one of the potential contaminants in honey.Solid-phase extraction is the key pretreatment procedure for analysis of chloramphenicol in honey.In this work,an on-line pretreatment liquid chromatography-tandem mass spectrometer system for sensitive,reliable and higher throughput analysis was developed.With the methylcellulose-immobilized reversed-phase column,sugars in a honey sample were efficiently removed in 1 min.As a result,the limit of quantitation of chloramphenicol was 20 pg/mL(0.2 μg/kg honey).     

Porous boronate affinity monolith for on-line extraction coupled to high-performance liquid chromatography for sensitive analysis of heterocyclic aromatic amines in food samples

A novel on-line solid-phase microextraction–high-performance liquid chromatography(SPME–HPLC)system was developed for the determination of heterocyclic aromatic amines(HAAs) in food samples. A poly(vinylphenylboronic acid-co-ethylene glycol dimethacrylate) polymer monolith was prepared for on-line efficient extraction and large-volume injection was used to increase the sensitivity of detection.The polymermonolith, based on a ternary porogen, was prepared by in situ polymerization of vinylphenylboronic acid(VPBA) and ethylene glycol dimethacrylate(EGDMA) in a fused-silica capillary column. It showed good permeability, high extraction capacity, and high selectivity. The column-tocolumn reproducibility was satisfactory, and the enrichment factors for HAAs were 3746–7414.Conditions influencing the on-line extraction efficiency, including p H of sample solutions, flow rate of extraction and desorption, and desorption volume, were investigated. The proposed method had low limit of detection(0.10–0.15 ng/L) and good linearity. Trace HAAs in roast beef and lamb samples were determined, and the amounts of 2-amino-3-methylimidazo[4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline, and 2-amino-3,4,7,8-tetramethyl-3H-imidazo[4,5-f]quinoxaline in these samples were 0.235–2.08 ng/g. The recoveries for the five HAAs ranged from74.3% to 119%, and the relative standard deviation(RSDs) were less than 8.2%. The results showed that the proposed on-line method was highly sensitive for monitoring HAAs in different food samples.     

TRACE METALS IN VANDA LAKE IN ANTARCTICA——A VERTICAL MIGRATION MODEL OF TRACE METALS IN CLOSED BASIN

Vanda Lake, a typical dimictic CaCl_2 type salt lake, is located in the Wright Valley inAntarctica. Based on the chemical and physical features of the salt lake water, the authorsdiscussed the vertical geochemical distribution of Fe, Mn, Pb, Cr, Cu, Co, Ni, Cd in the lake,and their vertical migration in lake waters, and have tried to set up a model of vertical mi-gration of these trace elements in the water of a closed chloride type salt lake.