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.     

同时测定无机离子的改良离子色谱法在河水和废水质量监控中的应用（英文）

In this study,our recent work on advanced ion chromatographic methods for the simultaneous determination of inorganic ionic species such as common anions(SO2-4,Cl-and NO-3) and cations(Na+,NH+4,K+,Mg2+,and Ca2+),nutrients(phosphate and silicate) and hydrogen ion/alkalinity are summarized first.Then,the applications using these methods for monitoring environmental water quality are also presented.For the determination of common anions and cations with nutrients,the separation was successfully performed by a polymethacrylate-based weakly acidic cation-exchange column of TSKgel Super IC-A/C(Tosoh,150 mm×6.0 mm i.d.) and a mixture solution of 100 mmol/L ascorbic acid and 4 mmol/L 18-crown-6 as acidic eluent with dual detection of conductivity and spectrophotometry.For the determination of hydrogen ion/alkalinity,the separation was conducted by TSKgel ODS-100Z column(Tosoh,150 mm×4.5 mm i.d.) modified with lithium dodecylsulfate and an eluent of 40 mmol/L LiCl/0.1 mmol/L lithium dodecylsulfate/0.05 mmol/L H2SO4 with conductivity detector.The differences of ion concentration between untreated and treated wastewater showed the variation of ionic species during biological treatment process in a sewage treatment plant.Occurrence and distribution of water-quality conditions were related to the bioavailability and human activity in watershed.From these results,our advanced ion chromatographic methods have contributed significantly for water quality monitoring of environmental waters.     

强碱阴离子交换树脂及碱性洗脱剂的离子排阻/阴离子交换色谱法同时测定NH4+ ，NO2-和NO3-（英文）

Ion-exclusion/anion-exchange chromatography(IEC/AEC) on a combination of a strongly basic anion-exchange resin in the OH——form with basic eluent has been developed.The separation mechanism is based on the ion-exclusion/penetration effect for cations and the anion-exchange effect for anions to anion-exchange resin phase.This system is useful for simultaneous separation and determination of ammonium ion(NH+4),nitrite ion(NO-2),and nitrate ion(NO-3) in water samples.The resolution of analyte ions can be manipulated by changing the concentration of base in eluent on a polystyrene-divinylbenzene based strongly basic anion-exchange resin column.In this study,several separation columns,which consisted of different particle sizes,different functional groups and different anion-exchange capacities,were compared.As the results,the separation column with the smaller anion-exchange capacity(TSKgel Super IC-Anion) showed well-resolved separation of cations and anions.In the optimization of the basic eluent,lithium hydroxide(LiOH) was used as the eluent and the optimal concentration was concluded to be 2 mmol/L,considering the resolution of analyte ions and the whole retention times.In the optimal conditions,the relative standard deviations of the peak areas and the retention times of NH+4,NO-2,and NO-3 ranged 1.28%-3.57% and 0.54%-1.55%,respectively.The limits of detection at signal-to-noise of 3 were 4.10 μmol/L for NH+4,1.87 μmol/L for NO-2 and 2.83 μmol/L for NO-3.     

Separation of strontium from associated elements with selective specific resin and extraction chromatography

In this paper,separation of Sr from associated elements（Na,K,Ca,Mg,and Ba） was carried out using an extraction chromatographic column packed with Sr selective specific resin consisting of an octanol solution of 4,4’（5’）-bis（t-butylcyclohexo）-18-crown-6 sorbed on an inert polymeric support.Using 8.0 mol/L HNO₃ as the eluent,Ba and associated elements were eluted immediately from the column, whereas Sr was strongly retained.The adsorbed Sr could then be stripped from the column as the eluent was changed to 0.05 mol/L HNO₃.Complete Sr/Ba separation was demonstrated to be feasible in that Ba could be washed from the column leaving pure Sr by adequate rinsing with 8.0 mol/L HNO₃. Furthermore,matrix effect could be effectively eliminated and the selectivity of the method was improved.The method was applied for the determination of Sr in the high purity barium carbonate （BaCO₃） product and seawater.The recoveries of Sr in 2 samples were determined to be 93.2%and 109%, respectively.     

Fast analysis of thiocyanate by ion-pair chromatography with direct conductivity detection on a monolithic column

Fast analysis of thiocyanate by ion-pair chromatography using a silica-based monolithic column and direct conductivity detection was carried out. Chromatographic separation was performed on a Chromolith Speed ROD RP-18e using tetrabutylammonium hydroxide （TBA）-phthalic acid-acetonitrile as eluent. The effects of eluent concentration, eluent pH value, column temperature and flow rate on retention time of thiocyanate were investigated. The optimized chromatographic conditions for the determination of thiocyanate were as follows： 0.25 mmol/L TBA-0.18 mmol/L phthalate-7% acetonitrile （pH 5.5） as eluent, column temperature of 30 ℃, and flow rate of 6.0 mL/min. Retention time of thiocyanate was less than 1 min under the conditions. Common anions （Cl^-, NO3 , SO42 and I^- ） did not interfere with the determination of thiocyanate. Detection limit （S/N = 3） of thiocyanate was 0.96 mg/L. Calibration graph between peak area and the concentration of thiocyanate was linear in the range of 2.0- 100.0 mg/L. Relative standard deviation （RSD） of chromatographic peak area was 1.4% （n = 5）. This method has been applied to the determination of thiocyanate in ionic liquids. Recoveries of thiocyanate after spiking were 100.5%.     

Synthesis and Characterization of a New Pure Inorganic 2D Network Based on [H_2W_（12）O_（42）]~（10-）

An isopolytungstate(NH4)6Na4[H2W12O42]·14H2O(1) has been synthesized in an aqueous solution and characterized by elemental analysis,IR spectroscopy,TG analysis,X-ray powder diffraction(XRD) and single-crystal X-ray diffraction.The result indicates a degradation from nitrilotriacetic acid(NTA) to NH3.The electrochemical analysis and thermal stability of 1 were also studied.The crystal data are as follows:H54N6Na4O56W12(Mr = 3332.65),orthorhombic,Pbca,a = 14.1497(15),b = 15.9414(16),c = 22.931(2) ,Z = 4,V = 5172.4(9) 3,Dc = 4.280 Mg/m3,μ = 26.729 mm-1,F(000) = 5904,the final R = 0.0809 and wR = 0.2104 for 4565(Rint = 0.1351) independent reflections.The β-[H2W12O42]10-clusters are linked through {Na2(OH2)3} groups into a 2D layer and are further connected into a 3D framework via hydrogen bonding interactions.     

Determination of catecholamines by ion chromatography coupled to acidic potassium permanganate chemiluminescence detection

A simple,fast,sensitive,highly selective and eco-friendly analytical method for the determination of catecholamines in human urine by ion chromatography（IC） with chemiluminescence（CL） detection was described in this paper.Using 12 mmol/L H₂SO₄ without any organic additive as eluent,three catecholamines including epinephrine（EP）,norepinephrine（NE） and dopamine（DA） were well separated on a cation-exchange column.The CL detection was based on the reaction of analytes with acidic potassium permanganate in the presence of formaldehyde as an enhancer.The absence of methanol and acetonitrile in eluent made the proposed method more sensitive and eco-friendly.Under the optimal conditions,the linear range of the proposed method was in the range of 0.02-0.5μg/mL.The limit of detection（LOD） was in the range of 0.6 and 5.1μg/L.The relative standard deviations （RSD） for 0.1μg/mL mixed standard solution were in the range of 0.8-1.9%（n = 11）.The method has been applied to the determination of catecholamines in human urine successfully.Excellent spiked recoveries were achieved for catecholamines ranged from 91.2%to 112.7%.     

FLAME ATOMIC ABSORPTION DETERMINATION OF COPPER IN CEREALS FOOD SAMPLES WITH THE PRECONCENTRATION OF POTASSIUM TETRATITANATE WHISKER

A simple and reliable method has been developed for separation and preconcentration of trace amounts of copper ions in cereals food for subsequent measurement by flame atomic absorption spectrometry （FAAS）. The Cu^2＋ ions are adsorbed selectively and quantitatively during the passage. The retained copper ions were desorbed from the potassium tetratitanate whisker with 10.0mL of 2mol/L sulphuric acid solutions as eluent and were determined by FAAS. The linear range was 0.05μg/mL-0.20μg/mL in the original solution with a correlation coefficient of 0.9998. The detection limit of the proposed method is 2. lng/mL in the original solution （3σ, n=9）. Determination of copper in standard ions showed that the proposed method has good accuracy （recovery was more than 95%）. The method was successfully applied for recovery and determination of copper in cereals food samples     

Approaches to the liquid chromatographic determination of carboxylic acids using potentiometric detection with a metallic copper electrode

Summary A metallic copper electrode is evaluated as a potentiometric detector for carboxylic acids. The application of this device to ion-exchange chromatography is illustrated by the determination of oxalate in urine. Oxalate was selectively detected in the presence of a 100-fold excess of sulphate after separation on a low-capacity methacrylate anion-exchange column using 0.7mM potassium hydrogen phthalate at pH 7.1 as eluent. Calibration plots were linear up to 50ppm of oxalate. Potentiometric detection has also been applied to ion-exclusion chromatography using 0.005% phosphoric acid as eluent. With this method detection limits of 0.2, 2.1, 5.0 and 5.3μg were obtained for formic, acetic, propionic and iso-butyric acids, respectively.     

高效液相色谱法测定人血清中α－细辛醚的方法

The HPLC method for analysis of α-Asaricin in human serum is simple, sensitive and accurate,A goodlinear correlation between α-Asaricin peak height and its concentration was obtained when α-Asaricin content liein the range of 4. 81×10￣(-9)～9. 61×10￣(-7) mmol/L.The lowest detection limit was 4.81×10￣(-9) mmol/L for serumsample.The recovery was 99.2±1.15%.The within day and day-to-day CVs were all less than 5.3%.Themethod is adequate for the pharmacokinetic study of α-Asaricin in human body.     

Oxidative coupling of methane over （Na2WO4＋Mn or Ce）/SiO2 catalysts： In situ measurement of electrical conductivity

The effects of manganese oxide or ceria promoters on the performance of Na2WO4/SiO2 catalysts for oxidative coupling of methane (OCM) are reported. The OCM reaction was performed in a continuous-flow microreactor at 800 ℃, atmospheric pressure and under GHSV = 13200 ml gC-1at h-1. Catalysts were characterized by in situ conductivity measurement, FT-IR spectroscopy, XRD, SEM and temperature programmed reduction analysis. Manganese oxide promoted Na2WO4/SiO2 is considered as one of the active and selective ca...     

Oxidation of glyoxal to glyoxylic acid by oxygen over V2O5/C catalyst

A novel vanadium oxide catalyst supported on active carbon was prepared by an incipient wetness impregnation method, and the precursor was obtained from oxalic acid aqueous solutions of NH4VO3. The catalyst was applied liquid phase oxidation of glyoxal to glyoxylic acid. It was found that V2O5/C catalyst exhibited obvious activity for glyoxal oxidation. Glyoxylic acid could be obtained without pH regulation during the reaction. By using this catalyst, the conversion of glyoxal and the yield of glyoxalic acid were 29.2% and 13.6%, respectively at 313 K and oxygen flow 0.1 L/rain after reaction for 10 h.     

Iodide analysis by ion chromatography on a new stationary phase of polystyrene-divinylbenzene agglomerated with polymerized-epichlorohydrin-dimethylamine

A new stationary phase for iodide ion analysis has been developed. The cationic polymerepichlorohydrin-dimethylamine(PEPI-DMA) was served as modifier in synthesizing polyelectrolyte sorbents and the macroporous polystyrene-divinylbenzene(PS-DVB) resin was used as support. The positively charged polymer(PEPI-DMA) was electrostatically bonded to a negatively charged particle(PS-DVB sulfonated). The new stationary phase was characterized by scanning electron microscopy(SEM), Fourier transform infrared(FTIR), elemental analysis, chemical adsorption and desorption measurements. The chromatographic evaluation of the new stationary phase was performed using various anions with a conductivity detector. The new stationary phase was also applied to the determination of iodide directly with a DC amperometric detector using a platinum working electrode and an Ag/Ag Cl reference electrode. The chromatographic conditions were optimized and the eluent solution contained 5 mmol/L HNO3 and 15 mmol/L Na NO3 at a flow rate of 1.0 m L/min and column temperature of 30 8C. The applied voltage of the DC amperometric detector was 0.9 V. Under the optimum conditions, the linear range of the method was 0.2–50 mg/L for iodide ion with a correlation coefficient of 0.9990. The detection limit was 0.05 mg/L(calculated at S/N = 3) and the relative standard deviations(RSD, n = 6) were all less than 1% for retention time, peak area and peak height. This method was also utilized for the determination of iodide ions in samples of povidone iodine solution and kelp samples with satisfactory results.     

High performance liquid chromatography analysis of p-aminophenol synthesized by nitrobenzene transfer hydrogenation using formic acid as hydrogen sourceEI北大核心CSCD

Qualitative analysis of the main by-product of 4-hydroxybenzamide in the synthesis of p-aminophenol bynitrobenzene transfer hydrogenation with formic acid as hydrogen source was carried out by electrospray ionization mass spectrometry. The reaction system was quantitatively analyzed by high performance liquid chromatography. The chromatographic conditions were shown as followsShim pack VP-ODS column250 mm× 4.6 mm5 μµmdetection wavelength of 254 nmVmethanolVbuffer solution=114.8 mmol/L sodium dihydrogen phosphate solution1.9 mmol/L dibasic sodium phosphate solutionas the mobile phase and the flow rate of 0.8 mL/min with a column temperature of 35. Nitrobenzenep-aminophenolaniline and formylaniline in the reaction system were quantitatively analyzed by standard curve method with methyl N-phenylcarbamate as internal standard. The correlation coefficientsR2were 0.99930.99950.9998 and 0.9992 for these analytes respectively. The relative standard deviations RSDs were less than 1.0% 0.3% 0.2% and 0.4% respectively. The recoveries were in the ranges of 95.5%-102.6%101.2%-104.8%95.1%-99.8% and 95.7%-101.1%respectively. This method can be used for the simultaneous determination of main and by-products in the transfer hydrogenation of nitrobenzene with formic acid as hydrogen source. © 2022, Youke Publishing Co.,Ltd. All rights reserved.     

Synthesis of Ethyl Oleate Catalyzed by Solid Superacid SO4^2-/TiO2/La3＋

Rare-earth compound solid superacid SO42-/TiO2/La3+ was prepared. Its catalytic activity was examined under different synthetic conditions for the esterification of propanoic acid and n-butyl alcohol as probing reaction. The optimum conditions were also found, which were the pH=8, the depositing time was 24 h, the mass fraction of La(NO3)3 used in solid superacid was 5%, the concentration of H2SO4 was 1.25 mol/L, the soaking time in H2SO4 was 16 h and the calcining temperature was 500 °C. The ethyl oleate was synthesized from oleic acid and ethanol in the presence of SO42-/TiO2/La3+. The optimum reaction conditions were obtained which were the reaction time was 6 h, molar ratio of oleic acid to ethanol was 1:4 and the mass fraction of catalyst was 4%.     

Chemo-enzymatic Synthesis of Z-Asp-Val-Tyr-NH_2——A Precursor Tripeptide of Thymopentin

Z-Asp-Val-Tyr-NH2,a precursor tripeptide of thymopentin(TP-5),was successfully synthesized by a combination of chemical and enzyme methods.Firstly,the precursor dipeptide Val-Tyr-NH2 was synthesized by a novel chemical method in four steps including the preparation of NCA-Val,the esterification of L-tyrosine and the ammonolysis of L-tyrosine ethyl ester,and the formation of Val-Tyr-NH2 from NCA-Val and L-Tyr-NH2.Secondly,a thermolysin,thermoase PC 10F was used to catalyze the formation of Z-Asp-Val-Tyr-NH2 in an aqueous/organic solvent diphase system with Z-Asp-OH and Val-Ty-NH2 as the substrates under thermodynamic control.The optimum conditions were pH=6.5,40 ℃,thermoase 100 mg,in 2-(N-morpholino) ethanesulfonic acid MES/NaOH(containing 5 mmol/L CaCl2) of n-butanol system(15/85,volume ratio) for 20 h in a maximum yield of 27.02%.     

Purification of L-Lysine in Simulated Moving Bed and Fixed-Bed Chromatography

 L-Lysine was produced by a microbial process utilizing a Corynebacterium glutamicum (ATCC 21799) strain. L-Lysine was purified from the cultivated medium by fixed-bed and simulated moving bed （SMB） chromatography. The separation conditions including pH, eluent concentration and Lys+ and Lys2+ adsorption isotherms were studied in batch adsorption. The column capacity, eluent flow rate and eluent concentration have been studied in fixed-bed chromatography. Maximum purification rate of lysine was obtained as 0.066 g/(g·h) (per gram resin and per hour) at an eluent flow rate of 10 mL/min in fixed-bed chromatography. The results obtained from SMB were 0.11 g/(g·h) for L-lysine purification rate and 96% for L-lysine recovery.     

高效液相色谱法测定肿瘤患者血清中唾液酸的含量

A method for the determination of sialic acid (SA) in serum with high performance liquid chromatography was established. The condition were Sheer C18 , 10μm , column, sulfuric acid solution (pH 3.0) eluent and UV-210 detection. The recovery and detection limit of SA were 99.42% and 0.003 nmol/L respectively. The calibrations curve was linear within the range of 0. 032-3.23 nmol/L. The SA in serum samples of 34 healthy subjects and 92 cancer patients were determined by this method.     

A Quinoline Derivated Chemosensor for Cu^2＋ Recognition

A quinoline derivative N-(2-hydroxyl-naphthylmethyl)-N-(quinol-8-yl)amine(2) was synthesized and characterized, which can selectively recognize Cu2+ over other metal ions such as Zn2+, Cd2+, Sn2+, Pb2+, Hg2+, Ni2+, Mg2+, Cr3+, Mn2+, Sr2+, K+, Ca2+, Na+, Ba2+ in acetonitrile/water(volume ratio 99:1). Cu2+ induced a new absorption peak at 464 nm in the absorption spectrum(ε=4.66×102 L·mol-1·cm-1) and quenched the fluorescence emission of quinoline derivative 2. The binding of quinoline derivative 2 to Cu2+ wa...     

Graphene Oxide Doped Poly（hydroxymethylated-3,4- ethylenedioxythiophene）： Enhanced Sensitivity for Electrochemical Determination of Rutin and Ascorbic Acid

A novel graphene oxide doped poly(hydroxymethylated-3,4-ethylenedioxythiophene)(PEDOT-MeOH/GO) composite film was synthesized and utilized as an efficient electrode material for simultaneous detection of rutin and ascorbic acid(AA). PEDOT-MeOH/GO films were synthesized on glassy carbon electrode(GCE) by a facile one-step electrochemical approach and were characterized by scanning electron microscopy, UV-Vis spectroscopy, FTIR spectra and electrochemical methods. Then the PEDOT-MeOH/GO/GCE was applied successfully in the simultaneous detection of rutin and AA. The results showed that the oxidation peak currents of rutin and AA obtained at the PEDOT-MeOH/GO/GCE were much higher than those at the traditional conducting polymer PEDOT/GO/GCE, PEDOT-MeOH/GCE, PEDOT/GCE and bare GCE. Under optimized conditions, the linear ranges for rutin and AA are 20 nmol/L-10 μmol/L and 8 μmol/L-1 mmol/L, respectively. The detection limit is 6 nmol/L for rutin and 2 μmol/L for AA(S/N = 3), which are lower than those of the reported electrochemical sensors.