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2016 Volume 33 Issue 2
2016, 33(2): 123-132
doi: 10.11944/j.issn.1000-0518.2016.02.150431
Abstract:
Catalytic conversion of carbon dioxide(CO2) to value-added hydrocarbons is of great environmental and social importance, which can not only reduce CO2 concentration in the atmosphere, but also conform with sustainable development strategy. This paper reviews the progress in catalytic conversion of CO2 to C2+ hydrocarbons over Fe-based catalyst. Reaction pathway and mechanism, catalyst preparation and reactor design are emphatically introduced. In addition, the future of hydrocarbons synthesis via CO2 hydrogenation is also summarized.
Catalytic conversion of carbon dioxide(CO2) to value-added hydrocarbons is of great environmental and social importance, which can not only reduce CO2 concentration in the atmosphere, but also conform with sustainable development strategy. This paper reviews the progress in catalytic conversion of CO2 to C2+ hydrocarbons over Fe-based catalyst. Reaction pathway and mechanism, catalyst preparation and reactor design are emphatically introduced. In addition, the future of hydrocarbons synthesis via CO2 hydrogenation is also summarized.
2016, 33(2): 133-143
doi: 10.11944/j.issn.1000-0518.2016.02.150432
Abstract:
As a solution to overcome the shortcomings of homogeneous Fenton reaction, heterogeneous Fenton catalytic oxidation technology has been intensively investigated in the field of water treatment due to the advantages of high removal efficiency under wide range of pH and easy separation and reutilization. This article firstly introduces the development of heterogeneous Fenton catalytic oxidation technology for the degradation of organic pollutants, the mechanisms of heterogeneous Fenton reaction as well as the characterization and experimental methods to study the mechanisms. The categories of heterogeneous Fenton catalysts are reviewed, including iron oxides, other metal oxides, and metal organic framework materials. Particularly, the methods to improve the catalytic activity and stability of heterogeneous Fenton catalysts are discussed, which include regulating the morphology, size and pore structure of the catalyst to improve the specific surface area, loading the catalysts onto carriers with high specific surface area, compositing the catalysts with other transition metal and introducing the outfield(such as light, ultrasonic and microwave). Finally, the future development of heterogeneous Fenton catalysts is pointed out.
As a solution to overcome the shortcomings of homogeneous Fenton reaction, heterogeneous Fenton catalytic oxidation technology has been intensively investigated in the field of water treatment due to the advantages of high removal efficiency under wide range of pH and easy separation and reutilization. This article firstly introduces the development of heterogeneous Fenton catalytic oxidation technology for the degradation of organic pollutants, the mechanisms of heterogeneous Fenton reaction as well as the characterization and experimental methods to study the mechanisms. The categories of heterogeneous Fenton catalysts are reviewed, including iron oxides, other metal oxides, and metal organic framework materials. Particularly, the methods to improve the catalytic activity and stability of heterogeneous Fenton catalysts are discussed, which include regulating the morphology, size and pore structure of the catalyst to improve the specific surface area, loading the catalysts onto carriers with high specific surface area, compositing the catalysts with other transition metal and introducing the outfield(such as light, ultrasonic and microwave). Finally, the future development of heterogeneous Fenton catalysts is pointed out.
2016, 33(2): 144-148
doi: 10.11944/j.issn.1000-0518.2016.02.150233
Abstract:
2,3-Dihydro-1,4-benzodioxins were prepared through a tandem reaction of epoxides and o-iodophenols catalyzed by CuBr/1,4,7-trisubstituted-1,4,7-triazonane with K2CO3 as the base at 110℃. All aryl and aliphatic epoxides reacted with o-iodophenols smoothly with yields of 64%~83%. The relationship between yields and substituent groups was described and the possible mechanism was discussed. The compounds were confirmed by NMR and element analysis.
2,3-Dihydro-1,4-benzodioxins were prepared through a tandem reaction of epoxides and o-iodophenols catalyzed by CuBr/1,4,7-trisubstituted-1,4,7-triazonane with K2CO3 as the base at 110℃. All aryl and aliphatic epoxides reacted with o-iodophenols smoothly with yields of 64%~83%. The relationship between yields and substituent groups was described and the possible mechanism was discussed. The compounds were confirmed by NMR and element analysis.
2016, 33(2): 149-154
doi: 10.11944/j.issn.1000-0518.2016.02.150216
Abstract:
A new nonlinear optical(NLO) organic material 1-(pyrene-1-yl)-3-(4-methoxyphenyl)acrylic ketone(PMPAK) was synthesized and characterized with 1H NMR, IR, HR-MS and elemental analysis. The three order NLO properties of PMPAK was tested by 4f phase-coherent imaging system which utilized Nd:YAG-Laser System as the light source. The laser pulse was set at the wavelength of 450 nm with the pulse duration of 4 ns(FWHM), thus the relevant parameters were determined as: the nonlinear refractive index n2=-1.84×10-16 m2/W, the nonlinear absorption coefficient β=2.53×10-9 m/W and the third-order nonlinear polarizability χ(3)=1.137×10-10 esu.
A new nonlinear optical(NLO) organic material 1-(pyrene-1-yl)-3-(4-methoxyphenyl)acrylic ketone(PMPAK) was synthesized and characterized with 1H NMR, IR, HR-MS and elemental analysis. The three order NLO properties of PMPAK was tested by 4f phase-coherent imaging system which utilized Nd:YAG-Laser System as the light source. The laser pulse was set at the wavelength of 450 nm with the pulse duration of 4 ns(FWHM), thus the relevant parameters were determined as: the nonlinear refractive index n2=-1.84×10-16 m2/W, the nonlinear absorption coefficient β=2.53×10-9 m/W and the third-order nonlinear polarizability χ(3)=1.137×10-10 esu.
2016, 33(2): 155-160
doi: 10.11944/j.issn.1000-0518.2016.02.150245
Abstract:
Sulfonated metallophthalocyanines are mainly used as oxidation regenerated catalyst in liquefied petroleum gas(LPG) sweetening process. Aggregation behavior of the five sulfonated metallophthalocyanines(MSPc, M=Fe,Co,Ni,Cu,Zn) in the same or different solvents was studied. The influencing factors of inactivation and the influence of aggregation behavior on activity of catalytic oxidation were investigated. The results show that the aggregation of sulfonated metallophthalocyanines is significantly affected by solvents. The aggregation aggravates with the increasing of polarity of the solvent and storage period. Besides, the aggregation of sulfonated metallophthalocyanines is also affected by central metals. The activity of CoSPc and CuSPc catalytic oxidation of thiol is markedly reduced nearly 20% because of the aggregation.
Sulfonated metallophthalocyanines are mainly used as oxidation regenerated catalyst in liquefied petroleum gas(LPG) sweetening process. Aggregation behavior of the five sulfonated metallophthalocyanines(MSPc, M=Fe,Co,Ni,Cu,Zn) in the same or different solvents was studied. The influencing factors of inactivation and the influence of aggregation behavior on activity of catalytic oxidation were investigated. The results show that the aggregation of sulfonated metallophthalocyanines is significantly affected by solvents. The aggregation aggravates with the increasing of polarity of the solvent and storage period. Besides, the aggregation of sulfonated metallophthalocyanines is also affected by central metals. The activity of CoSPc and CuSPc catalytic oxidation of thiol is markedly reduced nearly 20% because of the aggregation.
2016, 33(2): 161-168
doi: 10.11944/j.issn.1000-0518.2016.02.150221
Abstract:
Polyamidoamine(PAMAM)-2-pyridine carbaldehyde(Py) Schiff base dendrimers and their palladium complexes were prepared. Their structures were characterized by FT-IR, elemental analysis, ICP and TG-DSC. Catalytic performance of these complexes in Heck reaction was investigated. PAMAM-2-pyridine carbaldehyde Schiff base dendrimer palladium complexes show better catalytic activity in DMF. Using triethylamine(Et3N) as base, phenyliodide(PhI):10 mmol, n(PhI):n(AA):n(Et3N)=1:1.4:2.5(AA:acylic acid), n(Pd)=6.1×10-3 mmol(5.0G PAMAMPy-Pd). The yield is 90.1% with 100℃ and N2 for 24 min in 5 mL DMF under above optimal conditions. These catalysts can be recovered by the simple filtration and solvent washing. The yield of product can reach up to 82.0% when the catalyst is used for the third time.
Polyamidoamine(PAMAM)-2-pyridine carbaldehyde(Py) Schiff base dendrimers and their palladium complexes were prepared. Their structures were characterized by FT-IR, elemental analysis, ICP and TG-DSC. Catalytic performance of these complexes in Heck reaction was investigated. PAMAM-2-pyridine carbaldehyde Schiff base dendrimer palladium complexes show better catalytic activity in DMF. Using triethylamine(Et3N) as base, phenyliodide(PhI):10 mmol, n(PhI):n(AA):n(Et3N)=1:1.4:2.5(AA:acylic acid), n(Pd)=6.1×10-3 mmol(5.0G PAMAMPy-Pd). The yield is 90.1% with 100℃ and N2 for 24 min in 5 mL DMF under above optimal conditions. These catalysts can be recovered by the simple filtration and solvent washing. The yield of product can reach up to 82.0% when the catalyst is used for the third time.
2016, 33(2): 169-174
doi: 10.11944/j.issn.1000-0518.2016.02.150205
Abstract:
A novel triethoxysilyl-functionalized poly(phthalazinone ether nitrile)(PNAS) was synthesized by hydrolysis, acylation and 3-aminopropyltriethoxysilance-functionalization, and characterized by FTIR, 29Si NMR, DSC and TGA. The self-assembled polymer film was designed to serve as wear resistant coating for silicon surface. It has an excellent heat-resistance with a glass transition temperature and the temperature at which 5% mass loss at 329℃ and 492℃, respectively. The surface morphology of self-assembled film was studied by atomic force microscopy, while the friction performance was investigated using reciprocating friction tester. Comparing with the short chain self-assembled film, the friction coefficient of the prepared film is very low(about 0.07 at the loading of 400 nN), and the anti-wear behavior is good, with a lack of failure after sliding over 5 hours.
A novel triethoxysilyl-functionalized poly(phthalazinone ether nitrile)(PNAS) was synthesized by hydrolysis, acylation and 3-aminopropyltriethoxysilance-functionalization, and characterized by FTIR, 29Si NMR, DSC and TGA. The self-assembled polymer film was designed to serve as wear resistant coating for silicon surface. It has an excellent heat-resistance with a glass transition temperature and the temperature at which 5% mass loss at 329℃ and 492℃, respectively. The surface morphology of self-assembled film was studied by atomic force microscopy, while the friction performance was investigated using reciprocating friction tester. Comparing with the short chain self-assembled film, the friction coefficient of the prepared film is very low(about 0.07 at the loading of 400 nN), and the anti-wear behavior is good, with a lack of failure after sliding over 5 hours.
2016, 33(2): 175-180
doi: 10.11944/j.issn.1000-0518.2016.02.150223
Abstract:
Bisphenol-A epoxy resin E-51 was cured by [C6mim]FeCl4 and mixed amines at room temperature(20℃). Compared to other E-51 systems which were cured by aliphatic amine, E-51 systems cured by [C6mim]FeCl4/mixed amine have better mechanical properties, thermal properties, and aging properties. The effect of the amount of [C6mim]FeCl4 on the properties of the cured epoxy resin systems was also investigated. Tensile strength of the [C6mim]FeCl4/mixed amine cured E-51 system reaches 90 MPa, and the system maintains its excellent mechanical properties at high temperature(120℃). The TGA result shows that the decomposition temperature is 310℃ when the mass loss of epoxy system reaches 5%. Even after 7 days aging at 200℃, the tensile strength of the [C6mim]FeCl4/mixed amine cured epoxy resin system is 28 MPa. Therefore, the [C6mim]FeCl4/mixed amine cured epoxy resin system is a new type of epoxy resin cured system which can be applied under high temperature.
Bisphenol-A epoxy resin E-51 was cured by [C6mim]FeCl4 and mixed amines at room temperature(20℃). Compared to other E-51 systems which were cured by aliphatic amine, E-51 systems cured by [C6mim]FeCl4/mixed amine have better mechanical properties, thermal properties, and aging properties. The effect of the amount of [C6mim]FeCl4 on the properties of the cured epoxy resin systems was also investigated. Tensile strength of the [C6mim]FeCl4/mixed amine cured E-51 system reaches 90 MPa, and the system maintains its excellent mechanical properties at high temperature(120℃). The TGA result shows that the decomposition temperature is 310℃ when the mass loss of epoxy system reaches 5%. Even after 7 days aging at 200℃, the tensile strength of the [C6mim]FeCl4/mixed amine cured epoxy resin system is 28 MPa. Therefore, the [C6mim]FeCl4/mixed amine cured epoxy resin system is a new type of epoxy resin cured system which can be applied under high temperature.
2016, 33(2): 181-189
doi: 10.11944/j.issn.1000-0518.2016.02.150234
Abstract:
Raw corn straw/carboxymethyl cellulose composite hydrogel(RCS/CMC) with the water content of 97.47% was prepared. The dependence of the modulus on the hydrogel compositions, the dependence of the degradation behavior in the buffer solution, mass loss behavior in soil, soil hydration and maize seed germination on the ratio of soil and CMC/RCS hydrogel were studied. The experimental results show that the soil moisture increases by 1.00%~1.61% compared with the control test, the degradation percentage of the hydrogel in the buffer solution containing cellulose enzyme at 37℃ after 4 days is about 80%, and the mass loss in soil is about 94% after 25 days. Though the average germination time extends apparently in the presence of hydrogel, the germination rate significantly increases, especially, for the processing in relative humidity of 18%, 20%, 23%, 26%, 28% and 30%, respectively, the maize seed germination is inhibited because of the water stress, but the germination rate is up to 97%.
Raw corn straw/carboxymethyl cellulose composite hydrogel(RCS/CMC) with the water content of 97.47% was prepared. The dependence of the modulus on the hydrogel compositions, the dependence of the degradation behavior in the buffer solution, mass loss behavior in soil, soil hydration and maize seed germination on the ratio of soil and CMC/RCS hydrogel were studied. The experimental results show that the soil moisture increases by 1.00%~1.61% compared with the control test, the degradation percentage of the hydrogel in the buffer solution containing cellulose enzyme at 37℃ after 4 days is about 80%, and the mass loss in soil is about 94% after 25 days. Though the average germination time extends apparently in the presence of hydrogel, the germination rate significantly increases, especially, for the processing in relative humidity of 18%, 20%, 23%, 26%, 28% and 30%, respectively, the maize seed germination is inhibited because of the water stress, but the germination rate is up to 97%.
2016, 33(2): 190-199
doi: 10.11944/j.issn.1000-0518.2016.02.150219
Abstract:
A new compound, N,N-diethylammonium O,O'-(2-methyl-2,4-pentylene)dithiophosphate(PDP), was synthesized and characterized by elemental analysis, IR, NMR, and X-ray single crystal diffraction analysis. The crystallographic structure analysis reveal that PDP crystallizes in tetragonal system, I-4 space group, a=2.1357(3) nm, b=2.1357(3) nm, c=0.71892(11) nm, α=β=γ=90°, V=3.2792(10) nm3, Z=8, Dc=1.156 g/cm3, F(000)=1232, μ(MoKα)=0.412 mm-1, F(000)=1232, S=0.952, R=0.0664, wR=0.1791 [I>2σ(I)]. One-dimensional channel supramolecular network structure is formed by N-H…S and C-H…S interactions in the PDP crystal. PDP as a novel corrosion inhibitor for carbon steel in HCl solution was evaluated by mass loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy. The results show that PDP acts as a mixed type inhibitor with cathodic inhibition as the dominative action. The adsorption of PDP on carbon steel surface obeys Langmuir isotherm, and the corrosion inhibition belongs to both physi- and chemisorptions. The inhibition efficiency is up to 98.9% with PDP concentration of 140 mg/L in 1.0 mol/L HCl solution at 25℃.
A new compound, N,N-diethylammonium O,O'-(2-methyl-2,4-pentylene)dithiophosphate(PDP), was synthesized and characterized by elemental analysis, IR, NMR, and X-ray single crystal diffraction analysis. The crystallographic structure analysis reveal that PDP crystallizes in tetragonal system, I-4 space group, a=2.1357(3) nm, b=2.1357(3) nm, c=0.71892(11) nm, α=β=γ=90°, V=3.2792(10) nm3, Z=8, Dc=1.156 g/cm3, F(000)=1232, μ(MoKα)=0.412 mm-1, F(000)=1232, S=0.952, R=0.0664, wR=0.1791 [I>2σ(I)]. One-dimensional channel supramolecular network structure is formed by N-H…S and C-H…S interactions in the PDP crystal. PDP as a novel corrosion inhibitor for carbon steel in HCl solution was evaluated by mass loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy. The results show that PDP acts as a mixed type inhibitor with cathodic inhibition as the dominative action. The adsorption of PDP on carbon steel surface obeys Langmuir isotherm, and the corrosion inhibition belongs to both physi- and chemisorptions. The inhibition efficiency is up to 98.9% with PDP concentration of 140 mg/L in 1.0 mol/L HCl solution at 25℃.
2016, 33(2): 200-205
doi: 10.11944/j.issn.1000-0518.2016.02.150236
Abstract:
One novel macrocyclic triamine derived ligand N,N',N''-tris(2-hydroxypropyl)-1,4,7-triazacyclodecane and its transition metal complexes, [CoL] [ClO4]2 were synthesized and characterized by physico-chemical and spectroscopic methods. The crystal structure of [CoL][ClO4]2 was determined. The complex belongs to crystallographic system of monoclinic and space group:P2/N(1). The complex is hexacoordinate and the center Co atom exists in a distortion three prism coordination environment. The six coordinating atoms come from three nitrogen atoms and three oxygen atoms of the ligand. The average Co-N bond length and Co-O bond length are 0.2114(6) nm and 0.2097(6) nm, respectively. A regular supramolecular network structure are formed through the hydrogen bonding O…H-O between three oxygen atoms of the perchlorate with three oxygen atoms of the neighboring ligands.
One novel macrocyclic triamine derived ligand N,N',N''-tris(2-hydroxypropyl)-1,4,7-triazacyclodecane and its transition metal complexes, [CoL] [ClO4]2 were synthesized and characterized by physico-chemical and spectroscopic methods. The crystal structure of [CoL][ClO4]2 was determined. The complex belongs to crystallographic system of monoclinic and space group:P2/N(1). The complex is hexacoordinate and the center Co atom exists in a distortion three prism coordination environment. The six coordinating atoms come from three nitrogen atoms and three oxygen atoms of the ligand. The average Co-N bond length and Co-O bond length are 0.2114(6) nm and 0.2097(6) nm, respectively. A regular supramolecular network structure are formed through the hydrogen bonding O…H-O between three oxygen atoms of the perchlorate with three oxygen atoms of the neighboring ligands.
2016, 33(2): 206-212
doi: 10.11944/j.issn.1000-0518.2016.02.150194
Abstract:
A series of functionalized terpyridine ligands containing alkyl bridged imidazolium salts were designed and prepared in convenient manner. The transition metal complexes of these functionalized terpyridine ligands were investigated and the single crystal structure of Cu complex was successfully determined by X-ray diffraction. In the copper complex, Cu2+ was coordinated with two terpyridine units to form distorted octahedron symmetry. Monoclinic, space group P 21/c; a=1.7229(3) nm, b=1.5924(2) nm, c=2.1590(3) nm, α=90°, β=101.332(2)°, γ=90°, Mr=1298.09, V=5.8078(15) nm3, Dc=1.485 mg/m3, Z=4, F(000)=2684.
A series of functionalized terpyridine ligands containing alkyl bridged imidazolium salts were designed and prepared in convenient manner. The transition metal complexes of these functionalized terpyridine ligands were investigated and the single crystal structure of Cu complex was successfully determined by X-ray diffraction. In the copper complex, Cu2+ was coordinated with two terpyridine units to form distorted octahedron symmetry. Monoclinic, space group P 21/c; a=1.7229(3) nm, b=1.5924(2) nm, c=2.1590(3) nm, α=90°, β=101.332(2)°, γ=90°, Mr=1298.09, V=5.8078(15) nm3, Dc=1.485 mg/m3, Z=4, F(000)=2684.
2016, 33(2): 213-220
doi: 10.11944/j.issn.1000-0518.2016.02.150218
Abstract:
A Bi doped mesoporous TiO2 photocatalyst was prepared by solution impregnation method with mesoporous KIT-6 sieve as the carrier. The crystal structure and morphology of the photocatalyst was characterized with XRD, TEM, SEM, XPS, Raman spectrometer and physical adsorption instrument. Photocatalytic activity of the photocatalyst was investigated through degradation of Rhodamine B by UV-visible absorption spectrometry. The amount of doped Bi for impact on photocatalytic reaction rate and the kinetics of the photocatalytic degradation were studied. The results show that the Bi doped mesoporous TiO2 have a narrow pore size distribution(3~4 nm), and the light absorption band of photocatalyst is extended to visible light area. Therefore, the photocatalytic activity of Bi doped mesoporous TiO2 is significantly higher than that of commercial TiO2(P25). The photocatalytic degradation reaction of Rhodamine B is corresponding to an equation of first order reaction. The photocatalytic reaction rate constant increases with increasing amount of the doping Bi.
A Bi doped mesoporous TiO2 photocatalyst was prepared by solution impregnation method with mesoporous KIT-6 sieve as the carrier. The crystal structure and morphology of the photocatalyst was characterized with XRD, TEM, SEM, XPS, Raman spectrometer and physical adsorption instrument. Photocatalytic activity of the photocatalyst was investigated through degradation of Rhodamine B by UV-visible absorption spectrometry. The amount of doped Bi for impact on photocatalytic reaction rate and the kinetics of the photocatalytic degradation were studied. The results show that the Bi doped mesoporous TiO2 have a narrow pore size distribution(3~4 nm), and the light absorption band of photocatalyst is extended to visible light area. Therefore, the photocatalytic activity of Bi doped mesoporous TiO2 is significantly higher than that of commercial TiO2(P25). The photocatalytic degradation reaction of Rhodamine B is corresponding to an equation of first order reaction. The photocatalytic reaction rate constant increases with increasing amount of the doping Bi.
2016, 33(2): 221-228
doi: 10.11944/j.issn.1000-0518.2016.02.150264
Abstract:
Nb-containing capacitor material on foamed nickel substrate was prepared by the hydrothermal reaction with ammonium niobium oxalate and glucose as the starting meterials. The prepared samples was characterized by infrared spectroscopy(FTIR), scanning electron microscopy(SEM), X-ray diffraction(XRD) and electrochemical testing. By comparation of surface topography of products under different conditions, the optimal conditions of hydrothermal reaction for preparing Nb-capacitor material are established as:the molar ratio of glucose and ammonium oxalate is 7:1, and reaction temperature and time are 200℃ and 18 h, respectively. The Nb-containing oxide loaded on the foamed nickel is 0.3707 g/cm2. The maximum capacity of Nb-containing capacitor material reaches 189.47 F/g at the current density of 0.5 A/g. After 1000 cycles, the discharge capacitance of holding rate remains at 95%. This indicates that it is a promising candidate as the super capacitor materials.
Nb-containing capacitor material on foamed nickel substrate was prepared by the hydrothermal reaction with ammonium niobium oxalate and glucose as the starting meterials. The prepared samples was characterized by infrared spectroscopy(FTIR), scanning electron microscopy(SEM), X-ray diffraction(XRD) and electrochemical testing. By comparation of surface topography of products under different conditions, the optimal conditions of hydrothermal reaction for preparing Nb-capacitor material are established as:the molar ratio of glucose and ammonium oxalate is 7:1, and reaction temperature and time are 200℃ and 18 h, respectively. The Nb-containing oxide loaded on the foamed nickel is 0.3707 g/cm2. The maximum capacity of Nb-containing capacitor material reaches 189.47 F/g at the current density of 0.5 A/g. After 1000 cycles, the discharge capacitance of holding rate remains at 95%. This indicates that it is a promising candidate as the super capacitor materials.
2016, 33(2): 229-237
doi: 10.11944/j.issn.1000-0518.2016.02.150184
Abstract:
p-Hydroxybenzoic acid(p-HBA)-imprinted polymer particulates were prepared using p-HBA as the template, acrylamide(AM) as the functional monomer and ethylene glycol dimethacrylate as the crosslinker in three different amounts of p-HBA and under two different concentrations of pre-polymerization mixtures via precipitation polymerization. Their rebinding performances for p-HBA were characterized by high-performance liquid chromatography. The results reveal that both the amounts of p-HBA and the concentrations of pre-polymerization mixtures exhibit notable influence on the binding performances of p-HBA-imprinted polymers. The p-HBA-imprinted polymer(P2) with high affinity(k'=4.01) and selectivity for p-HBA is obtained when the amount of p-HBA is 1.0 mmol, which is corresponding to the molar ratio of 1:2(p-HBA/AM), in 37.5 mL of acetonitrile solvent. In addition, the imprinted polymer P2 was chosen as the adsorbent to make the molecularly imprinted solid phase extraction(MISPE) column and the MISPE method for the extraction of p-HBA was developed. The MISPE column capacities for p-HBA are 6.91 μg/100 mg and 1.93 μg/100 mg, respectively, which are determined under two different modes of loading samples. The rhizoma gastrodiae samples spiked with three different amounts of p-HBA are extracted and the recoveries of p-HBA range from 76.8% to 86.6%, with the RSD of 3.4%~6.2%(n=3). The results demonstrate that the p-HBA-imprinted polymer particulates prepared using AM as the functional monomer by precipitation polymerization are suitable as the adsorbent of solid phase extraction column for the selective separation and purification of p-HBA in the real sample of rhizoma gastrodiae.
p-Hydroxybenzoic acid(p-HBA)-imprinted polymer particulates were prepared using p-HBA as the template, acrylamide(AM) as the functional monomer and ethylene glycol dimethacrylate as the crosslinker in three different amounts of p-HBA and under two different concentrations of pre-polymerization mixtures via precipitation polymerization. Their rebinding performances for p-HBA were characterized by high-performance liquid chromatography. The results reveal that both the amounts of p-HBA and the concentrations of pre-polymerization mixtures exhibit notable influence on the binding performances of p-HBA-imprinted polymers. The p-HBA-imprinted polymer(P2) with high affinity(k'=4.01) and selectivity for p-HBA is obtained when the amount of p-HBA is 1.0 mmol, which is corresponding to the molar ratio of 1:2(p-HBA/AM), in 37.5 mL of acetonitrile solvent. In addition, the imprinted polymer P2 was chosen as the adsorbent to make the molecularly imprinted solid phase extraction(MISPE) column and the MISPE method for the extraction of p-HBA was developed. The MISPE column capacities for p-HBA are 6.91 μg/100 mg and 1.93 μg/100 mg, respectively, which are determined under two different modes of loading samples. The rhizoma gastrodiae samples spiked with three different amounts of p-HBA are extracted and the recoveries of p-HBA range from 76.8% to 86.6%, with the RSD of 3.4%~6.2%(n=3). The results demonstrate that the p-HBA-imprinted polymer particulates prepared using AM as the functional monomer by precipitation polymerization are suitable as the adsorbent of solid phase extraction column for the selective separation and purification of p-HBA in the real sample of rhizoma gastrodiae.
2016, 33(2): 238-244
doi: 10.11944/j.issn.1000-0518.2016.02.150188
Abstract:
A method for rapid separation and determination of four fatty acid monoglycerides, via ultra-performance convergence chromatography-mass spectrometry, was developed. Fatty acid monoglycerides were prepared by lipase-catalyzed glycerolysis using sunflower oil as the starting material. The main monoglycerides are monopalmitin, monostearin, monoolein, and monolinolein. The samples were dissolved by n-hexane/isopropanol(7:3 volume ratio), separated in 6 min on the column of ACQUITY UPC2 BEH 2-EP(100 mm×2.1 mm, 1.7 μm) with gradient elution of carbon dioxide and methanol/acetonitrile(1:1 volume ratio) system, and then detected by MS detector in the ESI+ mode. The results verified that the standard curves for the four components were obtained with good correlation coefficients(R2)>0.9983 in their concentration ranges. The limits of detection(LOD, S/N=3) for the four monoglycerides are in the range of 0.036~0.093 mg/L. The recoveries for the four monoglycerides at three spiked levels(low, middle, high) are 88.50%~110.00% with the relative standard deviations of 1.01%~4.04%. The proposed UPC2-MS method is featured with low detection limit, less time consuming, good separation and low cost. It would provide a new chromatographic technology platform for the detection of fatty acid esters.
A method for rapid separation and determination of four fatty acid monoglycerides, via ultra-performance convergence chromatography-mass spectrometry, was developed. Fatty acid monoglycerides were prepared by lipase-catalyzed glycerolysis using sunflower oil as the starting material. The main monoglycerides are monopalmitin, monostearin, monoolein, and monolinolein. The samples were dissolved by n-hexane/isopropanol(7:3 volume ratio), separated in 6 min on the column of ACQUITY UPC2 BEH 2-EP(100 mm×2.1 mm, 1.7 μm) with gradient elution of carbon dioxide and methanol/acetonitrile(1:1 volume ratio) system, and then detected by MS detector in the ESI+ mode. The results verified that the standard curves for the four components were obtained with good correlation coefficients(R2)>0.9983 in their concentration ranges. The limits of detection(LOD, S/N=3) for the four monoglycerides are in the range of 0.036~0.093 mg/L. The recoveries for the four monoglycerides at three spiked levels(low, middle, high) are 88.50%~110.00% with the relative standard deviations of 1.01%~4.04%. The proposed UPC2-MS method is featured with low detection limit, less time consuming, good separation and low cost. It would provide a new chromatographic technology platform for the detection of fatty acid esters.
