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2011 Volume 28 Issue 9
2011, 28(9): 977-985
doi: 10.3724/SP.J.1095.2011.00579
Abstract:
Porphyrins generally exist in the natural world and living things. They are the significant protoplasm. As the bulks of biomacromolecules, porphyrins and their derivates have the distinct quality for biomolecular recognition:molecular structure diversity, shape selectivity, good stability, high sensitivity and so on. The recent development on porphyrins' molecular recognition for DNA, amino acids, quinine, amine, etc is reviewed in this paper.
Porphyrins generally exist in the natural world and living things. They are the significant protoplasm. As the bulks of biomacromolecules, porphyrins and their derivates have the distinct quality for biomolecular recognition:molecular structure diversity, shape selectivity, good stability, high sensitivity and so on. The recent development on porphyrins' molecular recognition for DNA, amino acids, quinine, amine, etc is reviewed in this paper.
2011, 28(9): 986-992
doi: 10.3724/SP.J.1095.2011.00603
Abstract:
Polymer monolithic column has been widely applied in the fields of separation and catalysis because of their simple preparation procedure, homogeneous structure, high reproducibility, high column efficiency, and fast separation process. This review summarized the recent development of the applications of polymer monolithic column to the separation and analysis of biological samples. The problems and trends were also discussed.
Polymer monolithic column has been widely applied in the fields of separation and catalysis because of their simple preparation procedure, homogeneous structure, high reproducibility, high column efficiency, and fast separation process. This review summarized the recent development of the applications of polymer monolithic column to the separation and analysis of biological samples. The problems and trends were also discussed.
2011, 28(9): 993-998
doi: 10.3724/SP.J.1095.2011.00010
Abstract:
The reaction product between NdCl3·3i PrOH and Al(i-Bu)3 as catalysts was separated into a soluble and an insoluble part in hexane, and isoprene polymerization behaviors and characteristics of hexanesoluble and insoluble fractions were examined. The results indicated that the hexane-soluble fraction of the catalyst aging with the(Nd+Al) preformation had no activity at room temperature and at 70℃, and the catalytic precipitate obtained at 70℃ had no active too. The catalysts with the(Nd+IP+Al) preparation pattern showed activity of polymerization at both room temperature and 70℃. We speculated that there are two catalyst active centers of (isoprenyl)2NdCl and (isoprenyl)NdCl2 in the polymerization system. The catalytic prepared methods had no effect on the microstructures of polyisoprene(about 96%). The molecular mass of the polyisoprenes obtained by the suspension catalyst and precipitate catalyst was high(Mn >100×104) and the molecular mass distribution was narrow(Mw/Mn< 2.0), while the polyisoprene obtained by the clear solution catalyst had lower molecular mass(Mn< 30×104) and a very wide molecular mass distribution(Mw/Mn >5.0).
The reaction product between NdCl3·3i PrOH and Al(i-Bu)3 as catalysts was separated into a soluble and an insoluble part in hexane, and isoprene polymerization behaviors and characteristics of hexanesoluble and insoluble fractions were examined. The results indicated that the hexane-soluble fraction of the catalyst aging with the(Nd+Al) preformation had no activity at room temperature and at 70℃, and the catalytic precipitate obtained at 70℃ had no active too. The catalysts with the(Nd+IP+Al) preparation pattern showed activity of polymerization at both room temperature and 70℃. We speculated that there are two catalyst active centers of (isoprenyl)2NdCl and (isoprenyl)NdCl2 in the polymerization system. The catalytic prepared methods had no effect on the microstructures of polyisoprene(about 96%). The molecular mass of the polyisoprenes obtained by the suspension catalyst and precipitate catalyst was high(Mn >100×104) and the molecular mass distribution was narrow(Mw/Mn< 2.0), while the polyisoprene obtained by the clear solution catalyst had lower molecular mass(Mn< 30×104) and a very wide molecular mass distribution(Mw/Mn >5.0).
2011, 28(9): 999-1005
doi: 10.3724/SP.J.1095.2011.00621
Abstract:
The polystyrene(PSt) was synthesized by a single electron transfer living radical polymerization(SET-LRP) in a binary mixture of dimethyl sulfoxide(DMSO) and water using 2,2-dibromomethyl-1,3-dibromopropane as the multifunctional initiator, Cu0 powder and tris-(2-dimethylamino ethyl) amine(Me6-TREN) as catalytic system. The resulting polymers were analyzed by 1H NMR and GPC, the results showed that the distribution of the resulting polymer was narrow(Mw/Mn=1.20, MnGPC=25.3×103, 42.6% conversion) and the polymers prepared were star shape and had perfect chain ends -Br retention. In addition, the kinetic plots of polymerization were first order, which indicated a living polymerization process. The various factors which had affected the SET-LRP of St such as solvent, polymerization temperature and phase transfer catalyst(PTC) were studied, and the results showed that the H2O content in the binary mixtures increasing form 10% to 20%(volume fraction) led to a reduction in polymerization rate, which could be revealed by the apparent polymerization rate constant(kpapp) of 0.019 7 h-1 reducing from 0.026 4 h-1. Meanwhile the kpapp increased in according with enhancing the polymerization temperature, increasing the amount of catalyst or adding the PTC. The addition of PTC or increasing the amount of catalyst could improve the control of the polymerization.
The polystyrene(PSt) was synthesized by a single electron transfer living radical polymerization(SET-LRP) in a binary mixture of dimethyl sulfoxide(DMSO) and water using 2,2-dibromomethyl-1,3-dibromopropane as the multifunctional initiator, Cu0 powder and tris-(2-dimethylamino ethyl) amine(Me6-TREN) as catalytic system. The resulting polymers were analyzed by 1H NMR and GPC, the results showed that the distribution of the resulting polymer was narrow(Mw/Mn=1.20, MnGPC=25.3×103, 42.6% conversion) and the polymers prepared were star shape and had perfect chain ends -Br retention. In addition, the kinetic plots of polymerization were first order, which indicated a living polymerization process. The various factors which had affected the SET-LRP of St such as solvent, polymerization temperature and phase transfer catalyst(PTC) were studied, and the results showed that the H2O content in the binary mixtures increasing form 10% to 20%(volume fraction) led to a reduction in polymerization rate, which could be revealed by the apparent polymerization rate constant(kpapp) of 0.019 7 h-1 reducing from 0.026 4 h-1. Meanwhile the kpapp increased in according with enhancing the polymerization temperature, increasing the amount of catalyst or adding the PTC. The addition of PTC or increasing the amount of catalyst could improve the control of the polymerization.
2011, 28(9): 1006-1011
doi: 10.3724/SP.J.1095.2011.00708
Abstract:
A detailed research on the chloromethylation process was carried out. The chloromethylation of a phenolphthalein polyetherketone resin(PEK-C) was performed in a homogeneous reaction system using 1,4-bis(chloromethoxyl) butane as the chloromethylation reagent and concentrated sulforic acid as the solvent and catalyst. This method is environmentally friendly because of the absence of cancerogenic toxicity of BCMB. Furthermore, this method is more economical because of the low cost of BCMB. The effects of various factors on the chloromethylations were examined. The chemical structure and composition of the chloromethyled phenolphthalein polyetherketone resin(CMPEK-C) were characterized by Fourier transform infrared spectroscopy(FT-IR) and nuclear magnetic resonance(1H NMR). The experimental results show that the reaction mechanism consists of two kinds of reactions including electrophilic substitution on benzene ring and nucleophilic substitution accompanying by ether linkage fissiond. During the process in preparing CMPEK-C, along with the increase of chlorine content, Friedel-Crafts crosslinking reaction will occur. To prepare the chloromethylated PEK-C with high chlorine content and without obvious cross-linking, the suitable reaction conditions, such as reaction time, temperature influence and the used amount of 1,4-bis(chloromethoxy) butane(BCMB), need to be controlled. The reaction should be carried out at lower temperatures(about 10~30℃) because of the sensitivity of Friedel-Crafts reaction to temperature. Namely, there are two types of effects of reaction conditions on the chloromethylation of PEK-C, one is the influence on PEK-C chloromethylation degree, and the other is the influence on the remaining linearity for PEK-C. The CMPEK-C with 3.4 of chloromethylation degree and complete linearity was obtained under the optimized reaction conditions. The properties of CMPEK-C such as solubility in common organic solvents and thermal stability compared with PEK-C were also studied.
A detailed research on the chloromethylation process was carried out. The chloromethylation of a phenolphthalein polyetherketone resin(PEK-C) was performed in a homogeneous reaction system using 1,4-bis(chloromethoxyl) butane as the chloromethylation reagent and concentrated sulforic acid as the solvent and catalyst. This method is environmentally friendly because of the absence of cancerogenic toxicity of BCMB. Furthermore, this method is more economical because of the low cost of BCMB. The effects of various factors on the chloromethylations were examined. The chemical structure and composition of the chloromethyled phenolphthalein polyetherketone resin(CMPEK-C) were characterized by Fourier transform infrared spectroscopy(FT-IR) and nuclear magnetic resonance(1H NMR). The experimental results show that the reaction mechanism consists of two kinds of reactions including electrophilic substitution on benzene ring and nucleophilic substitution accompanying by ether linkage fissiond. During the process in preparing CMPEK-C, along with the increase of chlorine content, Friedel-Crafts crosslinking reaction will occur. To prepare the chloromethylated PEK-C with high chlorine content and without obvious cross-linking, the suitable reaction conditions, such as reaction time, temperature influence and the used amount of 1,4-bis(chloromethoxy) butane(BCMB), need to be controlled. The reaction should be carried out at lower temperatures(about 10~30℃) because of the sensitivity of Friedel-Crafts reaction to temperature. Namely, there are two types of effects of reaction conditions on the chloromethylation of PEK-C, one is the influence on PEK-C chloromethylation degree, and the other is the influence on the remaining linearity for PEK-C. The CMPEK-C with 3.4 of chloromethylation degree and complete linearity was obtained under the optimized reaction conditions. The properties of CMPEK-C such as solubility in common organic solvents and thermal stability compared with PEK-C were also studied.
2011, 28(9): 1012-1016
doi: 10.3724/SP.J.1095.2011.00375
Abstract:
Thiourea-chitosan-Co(Ⅱ) complex was prepared and characterized by FT-IR, UV-Vis absorbance spectra and TG-DTA methods, the antibacterial activities of thiourea-chitosan-Co(Ⅱ) complex against E.coli and St. aureus were studied in vitro. Moreover, the interaction between thiourea-chitosan-Co(Ⅱ) complex and bovine serum albumin(BSA) was also studied by ultraviolet and fluorescence spectroscopies. The results confirm that the complex is formed, and the antibacterial activities of thiourea-chitosan-Co(Ⅱ) complex is obviously enhanced comparing to its ligands and the complex can quench the intrinsic fluorescence of BSA.
Thiourea-chitosan-Co(Ⅱ) complex was prepared and characterized by FT-IR, UV-Vis absorbance spectra and TG-DTA methods, the antibacterial activities of thiourea-chitosan-Co(Ⅱ) complex against E.coli and St. aureus were studied in vitro. Moreover, the interaction between thiourea-chitosan-Co(Ⅱ) complex and bovine serum albumin(BSA) was also studied by ultraviolet and fluorescence spectroscopies. The results confirm that the complex is formed, and the antibacterial activities of thiourea-chitosan-Co(Ⅱ) complex is obviously enhanced comparing to its ligands and the complex can quench the intrinsic fluorescence of BSA.
2011, 28(9): 1017-1021
doi: 10.3724/SP.J.1095.2011.00489
Abstract:
A series of amphoteric polymeric electrolyte was prepared and their antibacterial activities and dissolving behaviour in water were investigated. A series of quaternized N,O-2-carboxyethyl chitosans(QCECs), which exhibit typical behaviour as amphoteric electrolyte, were obtained through the chemical modifications of N,O-(2-carboxyethyl) chitosan(N,O-2-CEC) by 2, 3-epoxypropyl trialkyl ammonium chlorides including glycidyl trimethyl ammonium chloride(GTMA), glycidyl triethyl ammonium chloride(GTEA), glycidyl tripropyl ammonium chloride(GTPA), glycidyl tributyl ammonium chloride(GTBA) and glycidyl dimethylbenzyl ammonium chloride(GDMBA). Substitution degree of quaternization(DQ) of QCECs was determined by the potentiometry, in which the variations of potential of solution with the volume of AgNO3 aqueous solution were measured. The isoeletric points(pHiep) of N,O-2-CEC and its quaternized derivatives were determined by spectrometry method. The antibacterial activities of chitosan derivatives including N,O-2-CEC and QCECs were evaluated according to their minimum inhibition concentrations(MICs) against E.coli, a typical Gram-negative bacterium, and S.aureus, a typical Gram-positive bacterium, determined by agar plate method. DQ values of QCECs were estimated in the range of 51.3%~59.1%, the pHiep of N,O-2-CEC and QCECs were in the range of 6.44~7.30 and the introduction of quaternizing group resulted in the accretion of pHiep. Except the product obtained from the modification of N,O-2-CEC by GTMA, the pHiep values of all other QCECs increased along with their DQ contents. All N,O-2-CEC and their quaternized derivatives showed improved antibacterial activity against E.coli and S.aureus. The MIC values of QCECs were lower than those of N,O-2-CEC. The increase of carbon chain length of alkyl and the presence of dimethyl benzyl in the quaternary ammonium groups could endow QCECs with much better antimicrobial activity.
A series of amphoteric polymeric electrolyte was prepared and their antibacterial activities and dissolving behaviour in water were investigated. A series of quaternized N,O-2-carboxyethyl chitosans(QCECs), which exhibit typical behaviour as amphoteric electrolyte, were obtained through the chemical modifications of N,O-(2-carboxyethyl) chitosan(N,O-2-CEC) by 2, 3-epoxypropyl trialkyl ammonium chlorides including glycidyl trimethyl ammonium chloride(GTMA), glycidyl triethyl ammonium chloride(GTEA), glycidyl tripropyl ammonium chloride(GTPA), glycidyl tributyl ammonium chloride(GTBA) and glycidyl dimethylbenzyl ammonium chloride(GDMBA). Substitution degree of quaternization(DQ) of QCECs was determined by the potentiometry, in which the variations of potential of solution with the volume of AgNO3 aqueous solution were measured. The isoeletric points(pHiep) of N,O-2-CEC and its quaternized derivatives were determined by spectrometry method. The antibacterial activities of chitosan derivatives including N,O-2-CEC and QCECs were evaluated according to their minimum inhibition concentrations(MICs) against E.coli, a typical Gram-negative bacterium, and S.aureus, a typical Gram-positive bacterium, determined by agar plate method. DQ values of QCECs were estimated in the range of 51.3%~59.1%, the pHiep of N,O-2-CEC and QCECs were in the range of 6.44~7.30 and the introduction of quaternizing group resulted in the accretion of pHiep. Except the product obtained from the modification of N,O-2-CEC by GTMA, the pHiep values of all other QCECs increased along with their DQ contents. All N,O-2-CEC and their quaternized derivatives showed improved antibacterial activity against E.coli and S.aureus. The MIC values of QCECs were lower than those of N,O-2-CEC. The increase of carbon chain length of alkyl and the presence of dimethyl benzyl in the quaternary ammonium groups could endow QCECs with much better antimicrobial activity.
2011, 28(9): 1022-1027
doi: 10.3724/SP.J.1095.2011.00588
Abstract:
Inhibiting effect of the curcumin(Cur) in combination with cis-diamminedichloroplatinum(DDP) on proliferation of COC1 cells was analyzed with MTT colorimetric assay. The morphological changes of COC1 cells were observed by inverted microscope. The result indicated that DDP of 2.5~10 mg/L dose combined with curcumin(Cur) of 5 mg/L dose could enhance the inhibiting effect and induce apoptosis compared with the case when only DDP was used. Meanwhile, curcumin of 5 mg/L dose could improve the sensitization of COC1 cells to DDP with 2.66 times. Optical microscopy results showed that COC1 cells had a marked decreased proliferation and a great amount of cells necrosis in DDP+ Cur group and DDP group than the control group. COC1 cells had lower diopter, scatter array, serious vacuolization treated with DDP+ Cur. The HPLC result indicated that the contents of DDP within tumor cells decreased lightly after dosage of Cur, but it had no statistically significant(P >0.05). In summary, curcumin combine with DDP can enhance the inhibiting effect on proliferation of COC1 cells, meanwhile, curcumin can improve the sensitization of COC1 cells to chemotherapeutics. However, the curcumin is unlikely to affect the amount of DDP within cells.
Inhibiting effect of the curcumin(Cur) in combination with cis-diamminedichloroplatinum(DDP) on proliferation of COC1 cells was analyzed with MTT colorimetric assay. The morphological changes of COC1 cells were observed by inverted microscope. The result indicated that DDP of 2.5~10 mg/L dose combined with curcumin(Cur) of 5 mg/L dose could enhance the inhibiting effect and induce apoptosis compared with the case when only DDP was used. Meanwhile, curcumin of 5 mg/L dose could improve the sensitization of COC1 cells to DDP with 2.66 times. Optical microscopy results showed that COC1 cells had a marked decreased proliferation and a great amount of cells necrosis in DDP+ Cur group and DDP group than the control group. COC1 cells had lower diopter, scatter array, serious vacuolization treated with DDP+ Cur. The HPLC result indicated that the contents of DDP within tumor cells decreased lightly after dosage of Cur, but it had no statistically significant(P >0.05). In summary, curcumin combine with DDP can enhance the inhibiting effect on proliferation of COC1 cells, meanwhile, curcumin can improve the sensitization of COC1 cells to chemotherapeutics. However, the curcumin is unlikely to affect the amount of DDP within cells.
2011, 28(9): 1028-1034
doi: 10.3724/SP.J.1095.2011.00623
Abstract:
Nine novel pyridazinone derivatives containing 1,2,4-triazolo and Schiff base were synthesized. Their structures were characterized by 1H NMR, 13C NMR, IR and elemental analyses. The preliminary bioassay showed that, under 500 mg/L concentrations, some of them exhibited certain anti-cucumber mosaic virus(CMV), G. zeae, F. oxysporum and C. mandshurica activities and fungicidal activities.
Nine novel pyridazinone derivatives containing 1,2,4-triazolo and Schiff base were synthesized. Their structures were characterized by 1H NMR, 13C NMR, IR and elemental analyses. The preliminary bioassay showed that, under 500 mg/L concentrations, some of them exhibited certain anti-cucumber mosaic virus(CMV), G. zeae, F. oxysporum and C. mandshurica activities and fungicidal activities.
2011, 28(9): 1035-1040
doi: 10.3724/SP.J.1095.2011.00577
Abstract:
The degradation efficiency of dichlorvos(DDVP) pesticide was conducted using a mixture of hydrogen peroxide and sodium persulfate, catalyzed by cobalt meso-tetrakis(4-sulfonatophenyl) porphyrin(CoTPPS4). Influencing factors on degradation ratio of dichlorvos were discussed, such as oxidant species, mixing ratio between oxidants, amount of additional catalyst, initial concentration of pesticide, pH value and temperature. Reaction kinetics of degradation reaction under optimized conditions was also studied. The degradation rate increased with the increases of catalyst dosage, pH(5~9) and reaction temperature as well as the decrease of initial concentration of pesticide. The results indicated that the degradation rate of 1.015 mol/L DDVP can reach to 72.8% after 7 h, when an additional volume of mixed oxidants of Na2S2O8 and H2O2(4/1, volume ratio) with 0.050 mol/L is 5 mL, the catalyst dosage is 2.4×10-3 g at pH=9, rate constant is 0.190 h-1. Kinetic studies suggest that the catalyzed oxidative degradation of dichlorvos is a pseudo-first-order reaction with the activation energy Ea of 5.052 kJ/mol.
The degradation efficiency of dichlorvos(DDVP) pesticide was conducted using a mixture of hydrogen peroxide and sodium persulfate, catalyzed by cobalt meso-tetrakis(4-sulfonatophenyl) porphyrin(CoTPPS4). Influencing factors on degradation ratio of dichlorvos were discussed, such as oxidant species, mixing ratio between oxidants, amount of additional catalyst, initial concentration of pesticide, pH value and temperature. Reaction kinetics of degradation reaction under optimized conditions was also studied. The degradation rate increased with the increases of catalyst dosage, pH(5~9) and reaction temperature as well as the decrease of initial concentration of pesticide. The results indicated that the degradation rate of 1.015 mol/L DDVP can reach to 72.8% after 7 h, when an additional volume of mixed oxidants of Na2S2O8 and H2O2(4/1, volume ratio) with 0.050 mol/L is 5 mL, the catalyst dosage is 2.4×10-3 g at pH=9, rate constant is 0.190 h-1. Kinetic studies suggest that the catalyzed oxidative degradation of dichlorvos is a pseudo-first-order reaction with the activation energy Ea of 5.052 kJ/mol.
2011, 28(9): 1041-1045
doi: 10.3724/SP.J.1095.2011.00625
Abstract:
In order to obtain a better understanding of the substituent effect on C60 derivatives, the 1H NMR, 13 C NMR and cyclic voltammetry of a series of 1,2-H(XPhCH2) C60(X=H, o-CH3, m-CH3, p-CH3, o-Br, m-Br, p-Br) derivatives have been examined. The results show that for NMR, the resonances of methylene protons and the methylene carbon atoms of the benzyls are affected significantly by the o-substituent, while the resonances of the fullerenyl protons and the C60 sp3 carbon atoms bonded to the addends are less affected by the o-, m- and p-substituent. As for the cyclic voltammetry, the redox properties of these derivatives are also less affected by the o-, m- and p-position difference of the substituent. However, the redox potentials of the derivatives containing CH3 PhCH2-are shifted negatively, and the redox potentials of the derivatives containing BrPhCH2—— are shift positively with respect to those of 1,2-H(PhCH2) C60. The results indicate that the inductive effect is probably the dominant factor in affecting the properties of C60 derivatives, which may be explored in modulating the electronic structure of C60 derivatives.
In order to obtain a better understanding of the substituent effect on C60 derivatives, the 1H NMR, 13 C NMR and cyclic voltammetry of a series of 1,2-H(XPhCH2) C60(X=H, o-CH3, m-CH3, p-CH3, o-Br, m-Br, p-Br) derivatives have been examined. The results show that for NMR, the resonances of methylene protons and the methylene carbon atoms of the benzyls are affected significantly by the o-substituent, while the resonances of the fullerenyl protons and the C60 sp3 carbon atoms bonded to the addends are less affected by the o-, m- and p-substituent. As for the cyclic voltammetry, the redox properties of these derivatives are also less affected by the o-, m- and p-position difference of the substituent. However, the redox potentials of the derivatives containing CH3 PhCH2-are shifted negatively, and the redox potentials of the derivatives containing BrPhCH2—— are shift positively with respect to those of 1,2-H(PhCH2) C60. The results indicate that the inductive effect is probably the dominant factor in affecting the properties of C60 derivatives, which may be explored in modulating the electronic structure of C60 derivatives.
2011, 28(9): 1046-1051
doi: 10.3724/SP.J.1095.2011.00568
Abstract:
On the basis of electropolymerization of dopamine(DA) at multiwalled carbon nanotubes(MWCNTs) modified glassy carbon(GC) electrodes, polydopamine(PDA)/MWCNTs/GC electrodes were prepared and characterized by electrochemical impedance spectroscopy(EIS) and cyclic voltammetry(CV). The electrode exhibited well-defined electrochemical behavior of DA in pH=7.4 phosphate buffer, producing higher oxidation currents than those on a bare GC electrode, and the direct electrochemical responses of 2.0 mmol/L ascorbic acid(AA) or K4Fe(CN)6 were inhibited, demonstrating the nano-enhancement effect of MWCNTs and the anti-anion electroanalysis selectivity due to use of the PDA film with the selective cationpermeability nature. DA electroanalysis was conducted at the electrode using CV and semi-derivative methods. The semi-derivative voltammetric peak height for DA oxidation is linear with DA concentration in the range of 0.08~1.76 μmol/L, and the linear regression equation in a phosphate buffer solution without AA or with 0.5 mmol/L coexisting AA is ipa-sd(μA/s1/2)=0.107+0.405c(μmol/L)(r2=0.986) or ipa-sd(μA/s1/2)=0.628+0.649c(μmol/L)(r2=0.992), both with detection limits of 8.0×10-8 mol/L(S/N=3). This method was used for rapid determination of DA in a DA hydrochloride injection sample with satisfactory results.
On the basis of electropolymerization of dopamine(DA) at multiwalled carbon nanotubes(MWCNTs) modified glassy carbon(GC) electrodes, polydopamine(PDA)/MWCNTs/GC electrodes were prepared and characterized by electrochemical impedance spectroscopy(EIS) and cyclic voltammetry(CV). The electrode exhibited well-defined electrochemical behavior of DA in pH=7.4 phosphate buffer, producing higher oxidation currents than those on a bare GC electrode, and the direct electrochemical responses of 2.0 mmol/L ascorbic acid(AA) or K4Fe(CN)6 were inhibited, demonstrating the nano-enhancement effect of MWCNTs and the anti-anion electroanalysis selectivity due to use of the PDA film with the selective cationpermeability nature. DA electroanalysis was conducted at the electrode using CV and semi-derivative methods. The semi-derivative voltammetric peak height for DA oxidation is linear with DA concentration in the range of 0.08~1.76 μmol/L, and the linear regression equation in a phosphate buffer solution without AA or with 0.5 mmol/L coexisting AA is ipa-sd(μA/s1/2)=0.107+0.405c(μmol/L)(r2=0.986) or ipa-sd(μA/s1/2)=0.628+0.649c(μmol/L)(r2=0.992), both with detection limits of 8.0×10-8 mol/L(S/N=3). This method was used for rapid determination of DA in a DA hydrochloride injection sample with satisfactory results.
2011, 28(9): 1052-1057
doi: 10.3724/SP.J.1095.2011.00602
Abstract:
The complexation of functional groups of polymers to metal ions was exploited to in situ prepare metal particles on the electrode surface. Poly(anthranilic acid)(PoABA) was first electrodeposited onto a glassy carbon electrode(GCE). Then copper ions(Cu2+) were chemically adsorbed within the PoABA film, and subsequently reduced by hydrazine hydrate forming copper particles(Cu0). The surface morphology and element composition of PoABA-Cu0 composite film was characterized by scanning electron microscopy and energy-dispersive X-ray ananlysis. The electrochemical properties of the PoABA-Cu0 modified electrode and its application for the detection of H2O2 were studied. The results show that there are well-distributed Cu particles in the PoABA film; the modified electrode exhibits well performance toward H2O2 electrocatalysis. When the number of potential scans for the polymerization of o-aminobenzoic acid is 10, the adsorption time of Cu2+ is 10 min, and the working voltage is-0.3 V, the PoABA-Cu0 modified electrode displays the best electroananlytic performance toward H2O2, where the linear H2O2 concentration range is 5.0×10-5~1.0×10-2 mol/L, the sensitivity is 96.34 μA·L/(mmol·cm), and the detection limit is 5.0×10-5 mol/L. Moreover, the sensing electrode shows a relatively good stability.
The complexation of functional groups of polymers to metal ions was exploited to in situ prepare metal particles on the electrode surface. Poly(anthranilic acid)(PoABA) was first electrodeposited onto a glassy carbon electrode(GCE). Then copper ions(Cu2+) were chemically adsorbed within the PoABA film, and subsequently reduced by hydrazine hydrate forming copper particles(Cu0). The surface morphology and element composition of PoABA-Cu0 composite film was characterized by scanning electron microscopy and energy-dispersive X-ray ananlysis. The electrochemical properties of the PoABA-Cu0 modified electrode and its application for the detection of H2O2 were studied. The results show that there are well-distributed Cu particles in the PoABA film; the modified electrode exhibits well performance toward H2O2 electrocatalysis. When the number of potential scans for the polymerization of o-aminobenzoic acid is 10, the adsorption time of Cu2+ is 10 min, and the working voltage is-0.3 V, the PoABA-Cu0 modified electrode displays the best electroananlytic performance toward H2O2, where the linear H2O2 concentration range is 5.0×10-5~1.0×10-2 mol/L, the sensitivity is 96.34 μA·L/(mmol·cm), and the detection limit is 5.0×10-5 mol/L. Moreover, the sensing electrode shows a relatively good stability.
2011, 28(9): 1058-1062
doi: 10.3724/SP.J.1095.2011.00607
Abstract:
Single phase micro-emulsified acid was studied in laboratory aimed at reducing its corrosion on pipes in the process of acidizing and increasing the penetration range of the layer. Micro-emulsified acid were prepared by mixing cationic surfactant with nonionic surfactant and other additives. The laboratory formation of the single phase micro-emulsified mud acid were as following(mass ratio):2.5% A-126, 2.5% CHJ-100, 1.2% n-butanol, 2.3% n-octanol, 0.5% W-221, 67.0% mud acid, 24.0% diesel oil. The result shows that its thermal stability can reach 81℃ with the suitable amount of additive of anionic surfactant W-221. The reactions between the micro-emulsified acid and P110S steel under both room temperature and 70℃ showed that the ratio of inhibiting corrosion has reached to 90.57% compared with mud acid of the same concentrations. Finally, the reaction between the acid and man-made rock core under 70℃ shows that the corrosion rate reduce to 0.5%.
Single phase micro-emulsified acid was studied in laboratory aimed at reducing its corrosion on pipes in the process of acidizing and increasing the penetration range of the layer. Micro-emulsified acid were prepared by mixing cationic surfactant with nonionic surfactant and other additives. The laboratory formation of the single phase micro-emulsified mud acid were as following(mass ratio):2.5% A-126, 2.5% CHJ-100, 1.2% n-butanol, 2.3% n-octanol, 0.5% W-221, 67.0% mud acid, 24.0% diesel oil. The result shows that its thermal stability can reach 81℃ with the suitable amount of additive of anionic surfactant W-221. The reactions between the micro-emulsified acid and P110S steel under both room temperature and 70℃ showed that the ratio of inhibiting corrosion has reached to 90.57% compared with mud acid of the same concentrations. Finally, the reaction between the acid and man-made rock core under 70℃ shows that the corrosion rate reduce to 0.5%.
2011, 28(9): 1063-1066
doi: 10.3724/SP.J.1095.2011.00610
Abstract:
The saturated and supersaturated characteristics of nitazoxanide in DMF, DMSO, methanol and acetone at different temperatures were investigated by using the laser detection technique. The crystallization metastable zone widths of nitazoxanide were obtained at different temperatures in the above four solvents. The results indicated that the solubility, supersolubility and the metastable zone width of nitazoxanide enhance with increasing temperature. At the same temperature, the metastable zone width of nitazoxanide relations as follows:acetone< DMSO< methanol< DMF.
The saturated and supersaturated characteristics of nitazoxanide in DMF, DMSO, methanol and acetone at different temperatures were investigated by using the laser detection technique. The crystallization metastable zone widths of nitazoxanide were obtained at different temperatures in the above four solvents. The results indicated that the solubility, supersolubility and the metastable zone width of nitazoxanide enhance with increasing temperature. At the same temperature, the metastable zone width of nitazoxanide relations as follows:acetone< DMSO< methanol< DMF.
2011, 28(9): 1067-1072
doi: 10.3724/SP.J.1095.2011.00631
Abstract:
The adsorptive properties of the D301R resin towards nitrobenzene in aqueous solution were investigated in details. The adsorption kinetic curves and adsorption isotherm curves were determined at different temperatures. An adsorption kinetic model was proposed. The equilibrium adsorption capacity, the adsorptive activation energy and the adsorption enthalpy were estimated. The experimental results showed that the adsorption kinetics follows a pseudo-second-order equation controlled by a surface process. The rate constant k2 is 3.74×10-2 g/(mg·min) at 300 K, which increases with the increase of temperature. The equilibrium adsorption capacity is 5.02 mg/g at 300 K, which decreases with the increase of temperature. The adsorptive activation energy is 39.02 kJ/mol. The adsorption isotherm is consistent with the Langmuir isotherm and the calculated adsorption enthalpy is about -22.47 kJ/mol. The hydrogen bonding was suggested to be responsible for nitrobenzene adsorption onto D301R resin.
The adsorptive properties of the D301R resin towards nitrobenzene in aqueous solution were investigated in details. The adsorption kinetic curves and adsorption isotherm curves were determined at different temperatures. An adsorption kinetic model was proposed. The equilibrium adsorption capacity, the adsorptive activation energy and the adsorption enthalpy were estimated. The experimental results showed that the adsorption kinetics follows a pseudo-second-order equation controlled by a surface process. The rate constant k2 is 3.74×10-2 g/(mg·min) at 300 K, which increases with the increase of temperature. The equilibrium adsorption capacity is 5.02 mg/g at 300 K, which decreases with the increase of temperature. The adsorptive activation energy is 39.02 kJ/mol. The adsorption isotherm is consistent with the Langmuir isotherm and the calculated adsorption enthalpy is about -22.47 kJ/mol. The hydrogen bonding was suggested to be responsible for nitrobenzene adsorption onto D301R resin.
2011, 28(9): 1073-1081
doi: 10.3724/SP.J.1095.2011.00565
Abstract:
A new method for the determination of trace Pb2+ by flame atomic absorption spectrometry(FAAS) after separation and preconcentration with molecular imprinting of chitosan/attapulgite(MICA) has been established. Under dynamic condition, the optimal pH of the solution, flow rate, elution conditions were obtained for preconcentration of trace Pb2+. And the effect of interfering ions was also investigated. It was found that Pb2+ could be quantitatively preconcentrated on MICA at pH=4.5. The flow rates of sample solutions and eluting solution with 1.0 mol/L HCl-0.1 mol/L methyl isobutyl ketone alcohol were 0.60 mL/min and 0.96 mL/min, respectively. The dynamic adsorption capacity of Pb2+ on MICA was 36.78 mg/g. The linear range for Pb2+ was 0~1.28 mg/L, correlation coefficient was 0.999 7, detection limit(3σ, n=11) for Pb2+ was 0.73 μg/L, and the relative standard deviation was 1.69%(n=6, ρ=0.08 mg/L), the recovery was in the range of 98.7%~101.4%. The method is convenient, highly precise and linear in a wide range. The method has been applied to the determination of trace amount Pb2+ in water samples with satisfactory results.
A new method for the determination of trace Pb2+ by flame atomic absorption spectrometry(FAAS) after separation and preconcentration with molecular imprinting of chitosan/attapulgite(MICA) has been established. Under dynamic condition, the optimal pH of the solution, flow rate, elution conditions were obtained for preconcentration of trace Pb2+. And the effect of interfering ions was also investigated. It was found that Pb2+ could be quantitatively preconcentrated on MICA at pH=4.5. The flow rates of sample solutions and eluting solution with 1.0 mol/L HCl-0.1 mol/L methyl isobutyl ketone alcohol were 0.60 mL/min and 0.96 mL/min, respectively. The dynamic adsorption capacity of Pb2+ on MICA was 36.78 mg/g. The linear range for Pb2+ was 0~1.28 mg/L, correlation coefficient was 0.999 7, detection limit(3σ, n=11) for Pb2+ was 0.73 μg/L, and the relative standard deviation was 1.69%(n=6, ρ=0.08 mg/L), the recovery was in the range of 98.7%~101.4%. The method is convenient, highly precise and linear in a wide range. The method has been applied to the determination of trace amount Pb2+ in water samples with satisfactory results.
2011, 28(9): 1082-1086
doi: 10.3724/SP.J.1095.2011.00352
Abstract:
A new method for the determination of Pb2+ in environmental water sample using crosslinked polyacrylonitrile as a solid-phase extractant and flame atomic absorption spectrometry(FAAS) as a sensitive detector has been developed. The adsorption of Pb2+ by crossslinked polyacrylonitrile and factors affecting the adsorption capacity were studied by AAS. The experimental results showed that at optimal adsorption conditions, e. g., pH of adsorbate solution was 5.4, static adsorption time was 1.5 h and adsorption procedure was carried at room temperature, polyacrylonitrile as adsorbent has high adsorption capacity for Pb2+ which can reach 49.6 mg/g. Adsorption rate was 90% during the 1.5 h static adsorption time. Using 0.10 mol/L chloride acid as the desorption solvent to desorb the adsorbates, the enrichment factor and the recovery were 50 times and 97% respectively. Under enrichment factor of 50 times, the detection limits(3σ) was 5.3 μg/L and the relative standard deviation(RSD) was 2.1%. The established method was extended to the determination of environmental samples and the results were satisfactory(recovery was 92.9%~97.6%). These results indicate that the polymer has good regenerate capability.
A new method for the determination of Pb2+ in environmental water sample using crosslinked polyacrylonitrile as a solid-phase extractant and flame atomic absorption spectrometry(FAAS) as a sensitive detector has been developed. The adsorption of Pb2+ by crossslinked polyacrylonitrile and factors affecting the adsorption capacity were studied by AAS. The experimental results showed that at optimal adsorption conditions, e. g., pH of adsorbate solution was 5.4, static adsorption time was 1.5 h and adsorption procedure was carried at room temperature, polyacrylonitrile as adsorbent has high adsorption capacity for Pb2+ which can reach 49.6 mg/g. Adsorption rate was 90% during the 1.5 h static adsorption time. Using 0.10 mol/L chloride acid as the desorption solvent to desorb the adsorbates, the enrichment factor and the recovery were 50 times and 97% respectively. Under enrichment factor of 50 times, the detection limits(3σ) was 5.3 μg/L and the relative standard deviation(RSD) was 2.1%. The established method was extended to the determination of environmental samples and the results were satisfactory(recovery was 92.9%~97.6%). These results indicate that the polymer has good regenerate capability.
2011, 28(9): 1087-1092
doi: 10.3724/SP.J.1095.2011.00627
Abstract:
The visible spectra and fluorescent spectra of safranine T(ST) solutions with the presence of sodium hexametaphosphat(SHMP) were investigated. The results showed that ST tends to aggregate when SHMP was presented and a heteropolymer appeared by electrostatic attraction between ST and SHMP in the HAc-NaAc buffer solution, which results in a new peak appeared in 476 nm in visible absorption spectra and the intensity of the absorbance and the fluorescence decreased. Meanwhile, the fluorescent lifetime of the ST was not changed, which suggested that the fluorescence of ST is statically quenched by SHMP. Based on the change of absorbance, we have established a new method to detect the SHMP. Under optimized conditions, the linear range was 1.0×10-6~1.1×10-5 mol/L with the detection limit of 3.4×10-7 mol/L. The application of the established method in the determination of tea drink samples gave a recovery rate of 95.0%~104.0%, with a relative standard deviation of less than 4.6%.
The visible spectra and fluorescent spectra of safranine T(ST) solutions with the presence of sodium hexametaphosphat(SHMP) were investigated. The results showed that ST tends to aggregate when SHMP was presented and a heteropolymer appeared by electrostatic attraction between ST and SHMP in the HAc-NaAc buffer solution, which results in a new peak appeared in 476 nm in visible absorption spectra and the intensity of the absorbance and the fluorescence decreased. Meanwhile, the fluorescent lifetime of the ST was not changed, which suggested that the fluorescence of ST is statically quenched by SHMP. Based on the change of absorbance, we have established a new method to detect the SHMP. Under optimized conditions, the linear range was 1.0×10-6~1.1×10-5 mol/L with the detection limit of 3.4×10-7 mol/L. The application of the established method in the determination of tea drink samples gave a recovery rate of 95.0%~104.0%, with a relative standard deviation of less than 4.6%.
2011, 28(9): 1093-1095
doi: 10.3724/SP.J.1095.2011.00709
Abstract:
Rosin-based poly(ether ester) elastomers were prepared from(R-PEGDA), citric acid and polyethylene glycol(PEG) via polycondensation reaction. TGA plots of the product showed that the temperature of 10% mass loss could be up to 300℃. The elastomers exhibited a wide range of tensile stress at break 0.26~0.62 MPa and elongation at break of 458%~338%.
Rosin-based poly(ether ester) elastomers were prepared from(R-PEGDA), citric acid and polyethylene glycol(PEG) via polycondensation reaction. TGA plots of the product showed that the temperature of 10% mass loss could be up to 300℃. The elastomers exhibited a wide range of tensile stress at break 0.26~0.62 MPa and elongation at break of 458%~338%.
2011, 28(9): 1096-1098
doi: 10.3724/SP.J.1095.2011.00533
Abstract:
A acidic ionic liquid[MIMPS]HSO4 was synthesized and used for the esterification of salicylic acid. Factors including reaction temperature, reaction time, ratio of reactant and amount of ionic liquid were investigated. It was found that the optimized conditions were at 95℃, microwave irradiation for 20 min, molar ratio of methanol to salicylic acid with 3:1, amount of [MIMPS]HSO4 10 mmol. The yield and selectivity of methyl salicylate were 91.9% and 99.0%, respectively.[MIMPS][HSO4] as a catalyst can be recycled for 4-times without obvious decrease in activity. Microwave irradiation could reduce reaction time under the same conditions. The yield of esterification decreased as the carbon chain increases, and also when the secondary alcohols were used instead of the primary alcohols.
A acidic ionic liquid[MIMPS]HSO4 was synthesized and used for the esterification of salicylic acid. Factors including reaction temperature, reaction time, ratio of reactant and amount of ionic liquid were investigated. It was found that the optimized conditions were at 95℃, microwave irradiation for 20 min, molar ratio of methanol to salicylic acid with 3:1, amount of [MIMPS]HSO4 10 mmol. The yield and selectivity of methyl salicylate were 91.9% and 99.0%, respectively.[MIMPS][HSO4] as a catalyst can be recycled for 4-times without obvious decrease in activity. Microwave irradiation could reduce reaction time under the same conditions. The yield of esterification decreased as the carbon chain increases, and also when the secondary alcohols were used instead of the primary alcohols.
