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2011 Volume 28 Issue 11
2011, 28(11): 1221-1228
doi: 10.3724/SP.J.1095.2011.00023
Abstract:
Phase-selective gelation of mixed un-miscible solvents is of great importance considering its applications in purification and separation, particularly in the recovery of spilled oil and in the purification of water. Gelators with phase-selective gelation properties could be polymers, micro-nano-particles or lowmolecular mass gelators(LMMGs). Compared with former two kinds of gelators, gelation using LMMGs as gelators is always reversible. Such reversibility could add additional advantages to practical applications of the gel systems. Progress in the studies of LMMGs with phase-selective gelation properties is reviewed according to the structures of the relevant gelators. Furthermore, prospectives of the studies and the potential applications of the phase-selective gelation phenomenon are also presented.
Phase-selective gelation of mixed un-miscible solvents is of great importance considering its applications in purification and separation, particularly in the recovery of spilled oil and in the purification of water. Gelators with phase-selective gelation properties could be polymers, micro-nano-particles or lowmolecular mass gelators(LMMGs). Compared with former two kinds of gelators, gelation using LMMGs as gelators is always reversible. Such reversibility could add additional advantages to practical applications of the gel systems. Progress in the studies of LMMGs with phase-selective gelation properties is reviewed according to the structures of the relevant gelators. Furthermore, prospectives of the studies and the potential applications of the phase-selective gelation phenomenon are also presented.
2011, 28(11): 1229-1238
doi: 10.3724/SP.J.1095.2011.00026
Abstract:
Two novel D-A type red dopants containing naphthothiadiazole(NT) or benzoselenadiazole(BS) electron withdrawing unit were synthesized. Through covalently attaching red dopants to polyfluorene(PFO) backbones and tuning the doping concentration, we obtained a series of red polymers. All these red polymers exhibit similar absorption spectra as PFO. Their photoluminescent(PL) spectra show not only blue emission from the PFO backbone but also red emission from the dopant. The relative intensity of the red emission increases successively with doping concentration. Unlike the PL spectra, the electroluminescent(EL) spectra of all the polymers predominantly exhibit red emission, which is attributed to the red dopants, with a weak blue emission from PFO backbone. It realizes completely energy transfer from PFO host to red dopants at 1% molar fraction doping level. The single-layer devices with the configuration of ITO/PEDOT:PSS/polymer/Ca/Al(PEDOT:poly(3,4-ethylenedioxythiophene); PSS:poly(styrenesulfonate)) show saturated red emission at 632 nm with a luminous efficiency of 1.61 cd/A and CIE of(0.63, 0.35) for PFR-10NT, and pure red emission at 620 nm with a luminous efficiency of 1.10 cd/A and CIE of(0.63, 0.36) for PFR-10BS, respectively.
Two novel D-A type red dopants containing naphthothiadiazole(NT) or benzoselenadiazole(BS) electron withdrawing unit were synthesized. Through covalently attaching red dopants to polyfluorene(PFO) backbones and tuning the doping concentration, we obtained a series of red polymers. All these red polymers exhibit similar absorption spectra as PFO. Their photoluminescent(PL) spectra show not only blue emission from the PFO backbone but also red emission from the dopant. The relative intensity of the red emission increases successively with doping concentration. Unlike the PL spectra, the electroluminescent(EL) spectra of all the polymers predominantly exhibit red emission, which is attributed to the red dopants, with a weak blue emission from PFO backbone. It realizes completely energy transfer from PFO host to red dopants at 1% molar fraction doping level. The single-layer devices with the configuration of ITO/PEDOT:PSS/polymer/Ca/Al(PEDOT:poly(3,4-ethylenedioxythiophene); PSS:poly(styrenesulfonate)) show saturated red emission at 632 nm with a luminous efficiency of 1.61 cd/A and CIE of(0.63, 0.35) for PFR-10NT, and pure red emission at 620 nm with a luminous efficiency of 1.10 cd/A and CIE of(0.63, 0.36) for PFR-10BS, respectively.
2011, 28(11): 1239-1243
doi: 10.3724/SP.J.1095.2011.00675
Abstract:
Two β-diketones with carbazole group were synthesized from carbazole and biphenyl. The β-diketones were characterized by 1H NMR, 13C NMR, MS, elemental analyses, thermoanalysis, UV-Vis absorption spectra and photoluminescence(PL) spectra. The β-diketones have high thermal stability, their 5% mass-reduction temperatures(ΔT5%) are 319℃ and 356℃, respectively. Their PL spectra lie in blue light zone with the maximum emission peaks of 443 nm and 455 nm. They are potential ligands for synthesizing metal ion complexes targeted for light-emitting materials.
Two β-diketones with carbazole group were synthesized from carbazole and biphenyl. The β-diketones were characterized by 1H NMR, 13C NMR, MS, elemental analyses, thermoanalysis, UV-Vis absorption spectra and photoluminescence(PL) spectra. The β-diketones have high thermal stability, their 5% mass-reduction temperatures(ΔT5%) are 319℃ and 356℃, respectively. Their PL spectra lie in blue light zone with the maximum emission peaks of 443 nm and 455 nm. They are potential ligands for synthesizing metal ion complexes targeted for light-emitting materials.
2011, 28(11): 1244-1249
doi: 10.3724/SP.J.1095.2011.00657
Abstract:
The preparation of nanosilica/polyurethane composites via in situ polymerization is reported. Nanosilica particles were first dispersed into polymer diols by high pressure shearing homogenizer(HPSH), then polymerization was carried out with the addition of the 4,4'-diphenylmethane diisocyanate(MDI) and the polymer diols containing ethylene glycol(EG) as the chain extender. Effects of the nanosilica content and dispersion method on the thermal and mechanical properties of nanosilica/polyurethane composites were investigated by thermogravimetric analysis(TGA), scanning electron microscopy(SEM), and dynamic mechanical thermal analysis(DMTA). The results indicated that the ——NCO groups in reaction mixture had reacted with the hydroxy on the surface of nanosilica particles during the in situ polymerization, and the chemical encapsulating ratio of the surface for nanosilica was 7%. Nanosilica particles(HPSH treated) in the nanocomposites were homogenously dispersed in the polyurethane matrix at the size of 30~40 nm, while the nanosilica treated by ultrasonic method aggregated so seriously that the diameter of the agglomerate size reached about 200 nm. Meanwhile, the tensile strength and elongation of the nanocomposites(HPSH treated) increased with increasing the nanosilica mass fraction(< 3%). When the mass fraction of silica was 3%, the tensile strength and enlongation reached the maximal values, and were 84.3 MPa and 438.7% respectively. Moreover, the polyurethane/nanosilica composites(HPSH treated) obtained by in situ polymerization had better thermal stability than pure polyurethane resins. Compared with the pure PU, the Tg, Td and T-50% of the nanocomposites samples(4% nanosilica) were increased by 17.2, 9 and 21℃, respectively.
The preparation of nanosilica/polyurethane composites via in situ polymerization is reported. Nanosilica particles were first dispersed into polymer diols by high pressure shearing homogenizer(HPSH), then polymerization was carried out with the addition of the 4,4'-diphenylmethane diisocyanate(MDI) and the polymer diols containing ethylene glycol(EG) as the chain extender. Effects of the nanosilica content and dispersion method on the thermal and mechanical properties of nanosilica/polyurethane composites were investigated by thermogravimetric analysis(TGA), scanning electron microscopy(SEM), and dynamic mechanical thermal analysis(DMTA). The results indicated that the ——NCO groups in reaction mixture had reacted with the hydroxy on the surface of nanosilica particles during the in situ polymerization, and the chemical encapsulating ratio of the surface for nanosilica was 7%. Nanosilica particles(HPSH treated) in the nanocomposites were homogenously dispersed in the polyurethane matrix at the size of 30~40 nm, while the nanosilica treated by ultrasonic method aggregated so seriously that the diameter of the agglomerate size reached about 200 nm. Meanwhile, the tensile strength and elongation of the nanocomposites(HPSH treated) increased with increasing the nanosilica mass fraction(< 3%). When the mass fraction of silica was 3%, the tensile strength and enlongation reached the maximal values, and were 84.3 MPa and 438.7% respectively. Moreover, the polyurethane/nanosilica composites(HPSH treated) obtained by in situ polymerization had better thermal stability than pure polyurethane resins. Compared with the pure PU, the Tg, Td and T-50% of the nanocomposites samples(4% nanosilica) were increased by 17.2, 9 and 21℃, respectively.
2011, 28(11): 1250-1255
doi: 10.3724/SP.J.1095.2011.00727
Abstract:
A superabsorbent polymer(SAP), poly(acrylic acid(AA)/acrylamido-2-methyl-propane sulfonic acid(AMPS))(PAAMPS), was synthesized by inverse suspension copolymerization using the uniform experiment design method. The effect of monomer molar ratios, the neutralization degrees, and the molar fractions of the initiator and the crosslinker(relative to total monomers amount) on the absorbencies in distilled water and 0.9% mass fraction of NaCl aqueous solution were examined. A simulation model of the quadratic regression equation was obtained. Comparison between the simulation and the experimental values was performed for the optimum formula and the single factor experiments. The results show that the simulation values and the experimental values are basically comparative. The optimum polymerization parameters are as follow:the molar fraction of AMPS is 8%, the neutralization degree of the monomers is 75%, the molar ratios of the crosslinker and the initiator(relative to total monomers amount) are 0.035% and 0.17% respectively, concentration of the total monomers is 30%, and the dispersing agent mass concentration relative to total monomers mass is 0.5%, the reaction temperature and time are 70℃ and 1.5 h, respectively. The absorbencies in distilled water and 0.9% NaCl aqueous solution under the optimum polymerization parameters are 1 600 and 130 g/g, respectively.
A superabsorbent polymer(SAP), poly(acrylic acid(AA)/acrylamido-2-methyl-propane sulfonic acid(AMPS))(PAAMPS), was synthesized by inverse suspension copolymerization using the uniform experiment design method. The effect of monomer molar ratios, the neutralization degrees, and the molar fractions of the initiator and the crosslinker(relative to total monomers amount) on the absorbencies in distilled water and 0.9% mass fraction of NaCl aqueous solution were examined. A simulation model of the quadratic regression equation was obtained. Comparison between the simulation and the experimental values was performed for the optimum formula and the single factor experiments. The results show that the simulation values and the experimental values are basically comparative. The optimum polymerization parameters are as follow:the molar fraction of AMPS is 8%, the neutralization degree of the monomers is 75%, the molar ratios of the crosslinker and the initiator(relative to total monomers amount) are 0.035% and 0.17% respectively, concentration of the total monomers is 30%, and the dispersing agent mass concentration relative to total monomers mass is 0.5%, the reaction temperature and time are 70℃ and 1.5 h, respectively. The absorbencies in distilled water and 0.9% NaCl aqueous solution under the optimum polymerization parameters are 1 600 and 130 g/g, respectively.
2011, 28(11): 1256-1262
doi: 10.3724/SP.J.1095.2011.00747
Abstract:
Four metal phthalocyanine tetraboxylic acid complexes(M-PTC) were synthesized and characterized by the IR, UV spectrometry and XRD. The catalytic activities of these complexes were screened using the epoxidation of olefins with molecular oxygen as oxidant. The factors including the category and amount of solvents, reaction temperature, as well as the amounts of isobutyradehyde(IBA) and catalyst were evaluated. It was found that Fe-PTC was the best catalyst. Under optimized conditions(ClCH2CH2Cl as the solvent, n(cyclooctene):n(catalyst):n(IBA)=4:0.002 5:16, 45℃, 5 h), the epoxidation of cyclooctene can give 91.1% yield, 91.1% selectivity and 1 457 turn over number(TON). Fe-PTC could be reused for 7 times without loss of catalytic activity. The IR spectra of the fresh-prepared and recovered catalysts indicated that the structure of the catalyst remained unchanged before and after reaction.
Four metal phthalocyanine tetraboxylic acid complexes(M-PTC) were synthesized and characterized by the IR, UV spectrometry and XRD. The catalytic activities of these complexes were screened using the epoxidation of olefins with molecular oxygen as oxidant. The factors including the category and amount of solvents, reaction temperature, as well as the amounts of isobutyradehyde(IBA) and catalyst were evaluated. It was found that Fe-PTC was the best catalyst. Under optimized conditions(ClCH2CH2Cl as the solvent, n(cyclooctene):n(catalyst):n(IBA)=4:0.002 5:16, 45℃, 5 h), the epoxidation of cyclooctene can give 91.1% yield, 91.1% selectivity and 1 457 turn over number(TON). Fe-PTC could be reused for 7 times without loss of catalytic activity. The IR spectra of the fresh-prepared and recovered catalysts indicated that the structure of the catalyst remained unchanged before and after reaction.
2011, 28(11): 1263-1268
doi: 10.3724/SP.J.1095.2011.00715
Abstract:
A facile demetalation of deuterohemin(DP) has been developed in a mixed solvent of acetic anhydride and hydrobromic acid. The influences of reaction time, bath temperature and the molar ratio on the yields were also investigated. Under the optimal reaction conditions for the demetalation of DP, the yield of 96.3% is obtained at the temperature of 100℃ for 2 h with the molar ratio of DP, hydrobromic acid and acetic anhydride about 1:6.3:61.2. A series of metallo-deuteroporphyrins was prepared and characterized by electrospray ionization tandem mass spectrometry(ESI-MS-MS), UV-Vis and IR. In addition, we also studied the effects of different solvents on the synthesis of metalloporphyrins, and the properties of metal cations on the shift of S and Q bands of porphyrin.
A facile demetalation of deuterohemin(DP) has been developed in a mixed solvent of acetic anhydride and hydrobromic acid. The influences of reaction time, bath temperature and the molar ratio on the yields were also investigated. Under the optimal reaction conditions for the demetalation of DP, the yield of 96.3% is obtained at the temperature of 100℃ for 2 h with the molar ratio of DP, hydrobromic acid and acetic anhydride about 1:6.3:61.2. A series of metallo-deuteroporphyrins was prepared and characterized by electrospray ionization tandem mass spectrometry(ESI-MS-MS), UV-Vis and IR. In addition, we also studied the effects of different solvents on the synthesis of metalloporphyrins, and the properties of metal cations on the shift of S and Q bands of porphyrin.
2011, 28(11): 1269-1273
doi: 10.3724/SP.J.1095.2011.00680
Abstract:
Employing heterogeneous reaction, 6-deoxy-tosyl-β-cyclodextrin(6-OTs-β-CD) was prepared by the reaction of β-CD with p-toluenesulfonyl chloride at low temperature in sodium hydroxide aqueous solution. The compound has been characterized by means of UV-Vis, IR, 1H NMR and 13C NMR spectroscopies. The mechanism of cyclodextrin mono tosylation was confirmed by 1H NMR. The effect of hydrolysis factors on product and the influence of reaction conditions on the yield were investigated. Under optimal reaction conditions molar ratio of reactant n(TsCl):n(CD)=4:1, alkali concentration 0.75 mol/L, mass fraction of reactants 4.7%, reaction temperature 0℃ and reaction time 5 h, a yield of 43.4% can be obtained.
Employing heterogeneous reaction, 6-deoxy-tosyl-β-cyclodextrin(6-OTs-β-CD) was prepared by the reaction of β-CD with p-toluenesulfonyl chloride at low temperature in sodium hydroxide aqueous solution. The compound has been characterized by means of UV-Vis, IR, 1H NMR and 13C NMR spectroscopies. The mechanism of cyclodextrin mono tosylation was confirmed by 1H NMR. The effect of hydrolysis factors on product and the influence of reaction conditions on the yield were investigated. Under optimal reaction conditions molar ratio of reactant n(TsCl):n(CD)=4:1, alkali concentration 0.75 mol/L, mass fraction of reactants 4.7%, reaction temperature 0℃ and reaction time 5 h, a yield of 43.4% can be obtained.
2011, 28(11): 1274-1279
doi: 10.3724/SP.J.1095.2011.00688
Abstract:
Two novel molecular receptors based on thiosemicarbazide, compound 3a(1, 3-bis(otolueneoxoacetylthio-semicarbazideacyl) benzene) and compound 3b(1, 3-bis(p-tolueneoxoacetylthiosemicarbazideacyl) benzene), have been designed and synthesized under solid-liquid phase transfer catalysis conditions. The binding properties for anions such as F-, AcO-, Cl-, Br- and I- in DMSO have been examined by UV-Vis and 1H NMR spectroscopy. The results show a high selectivity for F- and AcO-, however, no obvious interaction was found for Cl-, Br-, and I-. The 1H NMR combined with Job curves indicates that a 1:1 stoichiometry complex is formed between the receptors and the anions through hydrogen bonding interactions. In view of these results, the influences of the number of NH binding points and steric effect on binding properties were discussed. The receptor compound 3b can form much more hydrogen-bonding interactions due to the presence of many NH binding points, with larger association constant(Ks) than that of thiourea receptor. Compared compound 3a with 3b, large steric effect prevent the combination between compound 3a and anions. In terms of F- and AcO-, association constant of compound 3a and 3b followed the same tendency Ks(F-) >Ks(AcO-), owing to the better fit of size and shape between the receptors and F-.
Two novel molecular receptors based on thiosemicarbazide, compound 3a(1, 3-bis(otolueneoxoacetylthio-semicarbazideacyl) benzene) and compound 3b(1, 3-bis(p-tolueneoxoacetylthiosemicarbazideacyl) benzene), have been designed and synthesized under solid-liquid phase transfer catalysis conditions. The binding properties for anions such as F-, AcO-, Cl-, Br- and I- in DMSO have been examined by UV-Vis and 1H NMR spectroscopy. The results show a high selectivity for F- and AcO-, however, no obvious interaction was found for Cl-, Br-, and I-. The 1H NMR combined with Job curves indicates that a 1:1 stoichiometry complex is formed between the receptors and the anions through hydrogen bonding interactions. In view of these results, the influences of the number of NH binding points and steric effect on binding properties were discussed. The receptor compound 3b can form much more hydrogen-bonding interactions due to the presence of many NH binding points, with larger association constant(Ks) than that of thiourea receptor. Compared compound 3a with 3b, large steric effect prevent the combination between compound 3a and anions. In terms of F- and AcO-, association constant of compound 3a and 3b followed the same tendency Ks(F-) >Ks(AcO-), owing to the better fit of size and shape between the receptors and F-.
2011, 28(11): 1280-1285
doi: 10.3724/SP.J.1095.2011.00734
Abstract:
The anti-tumor effects of the polymer-paclitaxel conjugate micelles and free paclitaxel on H22 liver cancer bearing mice were evaluated. After 10 days drug administration, the tumor volume inhibition rates(VIR) of free paclitaxel group, polymer-paclitaxel conjugate micelles group at doses of 3 mg/kg, and the micelles group at doses of 6 mg/kg are 22%, 49%, and 67%, respectively. In addition, the tumor weight inhibition rates(WIR) are 29%, 45%, and 47%, respectively. Protein expression results show that paclitaxel micelles group has higher expression of p53 and lower expression of bcl-2. All these results indicate that the anti-tumor effect of polymer-paclitaxel conjugate micelles is stronger than free paclitaxel.
The anti-tumor effects of the polymer-paclitaxel conjugate micelles and free paclitaxel on H22 liver cancer bearing mice were evaluated. After 10 days drug administration, the tumor volume inhibition rates(VIR) of free paclitaxel group, polymer-paclitaxel conjugate micelles group at doses of 3 mg/kg, and the micelles group at doses of 6 mg/kg are 22%, 49%, and 67%, respectively. In addition, the tumor weight inhibition rates(WIR) are 29%, 45%, and 47%, respectively. Protein expression results show that paclitaxel micelles group has higher expression of p53 and lower expression of bcl-2. All these results indicate that the anti-tumor effect of polymer-paclitaxel conjugate micelles is stronger than free paclitaxel.
2011, 28(11): 1286-1291
doi: 10.3724/SP.J.1095.2011.00703
Abstract:
Six different natural flavonoids with similar structures, quercetin, kaempferol, luteolin, naringenin, baicalein, and apigenin were selected to examine the redox system between flavonoids and Ce(Ⅳ) using ultraviolet spectrophotometry and microtitration methods. According to their responding difference to Ce(Ⅳ), the mechanism of the reaction and the contribution of phenolic hydroxyls on different sites of the chromone to the antioxidation activity were investigated. The result indicates that the 3-OH of the pyrone ring is a sensitive site to react with Ce(Ⅳ) involving the proton dissociation, and the obtained product has a strong absorbance at 294 nm. The 3'-OH and 4'-OH on the B ring of the 2-phenyl-chromone are also the sensitive sites to oxidants since 4'-OH dissociates and forms intramolecular hydrogen bonding. The hydroxyl on ring C is more sensitive to Ce(Ⅳ) than that on ring A. The antioxidant capacity order of the six compounds is:Quercetin >Kaempferol >Luteoin >Apigenin >Baicalein >Naringenin, which is consistent with the sensitivity of spectral response of the six compounds to Ce(Ⅳ).
Six different natural flavonoids with similar structures, quercetin, kaempferol, luteolin, naringenin, baicalein, and apigenin were selected to examine the redox system between flavonoids and Ce(Ⅳ) using ultraviolet spectrophotometry and microtitration methods. According to their responding difference to Ce(Ⅳ), the mechanism of the reaction and the contribution of phenolic hydroxyls on different sites of the chromone to the antioxidation activity were investigated. The result indicates that the 3-OH of the pyrone ring is a sensitive site to react with Ce(Ⅳ) involving the proton dissociation, and the obtained product has a strong absorbance at 294 nm. The 3'-OH and 4'-OH on the B ring of the 2-phenyl-chromone are also the sensitive sites to oxidants since 4'-OH dissociates and forms intramolecular hydrogen bonding. The hydroxyl on ring C is more sensitive to Ce(Ⅳ) than that on ring A. The antioxidant capacity order of the six compounds is:Quercetin >Kaempferol >Luteoin >Apigenin >Baicalein >Naringenin, which is consistent with the sensitivity of spectral response of the six compounds to Ce(Ⅳ).
2011, 28(11): 1292-1297
doi: 10.3724/SP.J.1095.2011.00718
Abstract:
A new fluorescence-enhanced Pd2+ probe RPd5 was synthesized which shows both fluorescent and colorimetric responses to Pd2+ within 16 minutes. The fluorescent intensity was enhanced 40 times. With a pKa value of 3.96 ±0.01, it can detect Pd2+ in a wide pH range, especially in the neutral pH environment. RPd5 has the detection limit of 2.31×10-6 mol/L suggesting its high sensitivity for Pd2+ detection. Proof-ofconcept experiments demonstrate its potential application for Pd2+ detection in real soil and water samples. Additionally, RPd5 can be loaded as test paper for Pd2+ evaluation in the clean water solution.
A new fluorescence-enhanced Pd2+ probe RPd5 was synthesized which shows both fluorescent and colorimetric responses to Pd2+ within 16 minutes. The fluorescent intensity was enhanced 40 times. With a pKa value of 3.96 ±0.01, it can detect Pd2+ in a wide pH range, especially in the neutral pH environment. RPd5 has the detection limit of 2.31×10-6 mol/L suggesting its high sensitivity for Pd2+ detection. Proof-ofconcept experiments demonstrate its potential application for Pd2+ detection in real soil and water samples. Additionally, RPd5 can be loaded as test paper for Pd2+ evaluation in the clean water solution.
2011, 28(11): 1298-1304
doi: 10.3724/SP.J.1095.2011.00729
Abstract:
The α-cyclodextrin(CD) modified organic monolithic materials were synthesized and applied for the enrichment of polyaromatic compounds from environmental samples. Application of the modified materials in the solid extraction-room temperature phosphores(SPE-RTP) were studied and compared. The room temperature phosphorescence behaviors of 14 organic compounds on the α-CD modified substrate were examined. Compared with the β-CD modified material, the α-CD modified monolithic materials have less RTP background and therefore better sensitivity as well as enrichment capabilities for the double ring aromatic substances. The partition constants of naphthlene and 7,8-benzoquinolin on α-CD modified monolith were found to be 5.03×103 and 2.94×102, respectively, indicating that α-CD modified monolith has higher selectivity for naphthlene. Naphthol can form inclusion complex also with α-CD modified monolith. However, because of the large polarity and solubility in water, the extraction efficiency at higher concentration is relatively low. The largest enrichment volume for the concentration of 5×10-11 mol/mL naphthlene is 300 mL. With SPE-RTP, the detection limits for naphthlene and 7,8-benzoquinolin are 9.80×10-12 mol/mL and 4.60×10-11 mol/mL, respectively. The linear ranges are 5.00×10-11~8.00×10-9 mol/mL and 6.00×10-11~5.00×10-10 mol/mL, respectively, with RSD less than 3.7%. α-CD modified membrane was applied to the determination of naphthalene in polluted soil samples and results were further verified by GC-MS. With one step extraction by cyclohexane and then followed by SPE-RTP, naphthlene can be selectively concentrated from soil samples. With 0.012 8 mg naphthlene spiked in the soil samples, the recovery is(104.9 ±6.5)%. The concentration of naphthlene in the soil samples was determined as(5.61 ±0.12) mg/kg, which was in accord with the results of GC-MS.
The α-cyclodextrin(CD) modified organic monolithic materials were synthesized and applied for the enrichment of polyaromatic compounds from environmental samples. Application of the modified materials in the solid extraction-room temperature phosphores(SPE-RTP) were studied and compared. The room temperature phosphorescence behaviors of 14 organic compounds on the α-CD modified substrate were examined. Compared with the β-CD modified material, the α-CD modified monolithic materials have less RTP background and therefore better sensitivity as well as enrichment capabilities for the double ring aromatic substances. The partition constants of naphthlene and 7,8-benzoquinolin on α-CD modified monolith were found to be 5.03×103 and 2.94×102, respectively, indicating that α-CD modified monolith has higher selectivity for naphthlene. Naphthol can form inclusion complex also with α-CD modified monolith. However, because of the large polarity and solubility in water, the extraction efficiency at higher concentration is relatively low. The largest enrichment volume for the concentration of 5×10-11 mol/mL naphthlene is 300 mL. With SPE-RTP, the detection limits for naphthlene and 7,8-benzoquinolin are 9.80×10-12 mol/mL and 4.60×10-11 mol/mL, respectively. The linear ranges are 5.00×10-11~8.00×10-9 mol/mL and 6.00×10-11~5.00×10-10 mol/mL, respectively, with RSD less than 3.7%. α-CD modified membrane was applied to the determination of naphthalene in polluted soil samples and results were further verified by GC-MS. With one step extraction by cyclohexane and then followed by SPE-RTP, naphthlene can be selectively concentrated from soil samples. With 0.012 8 mg naphthlene spiked in the soil samples, the recovery is(104.9 ±6.5)%. The concentration of naphthlene in the soil samples was determined as(5.61 ±0.12) mg/kg, which was in accord with the results of GC-MS.
2011, 28(11): 1305-1310
doi: 10.3724/SP.J.1095.2011.00572
Abstract:
The adsorptions of three licorice derivatives including, isoliquiritin, liquiritin and glycyrrhizic acid on multi-walled carbon nanotubes(MWNTs), were investigated using UV and HPLC techniques. The effects of adsorption time, initial concentration, solution volume and its pH value on the adsorption of ciprofloxacin are examined. MWNTs have totally different adsorptive capacities toward the three main components. In the multi-component competitive adsorption examination, a noncompetitive adsorption process was observed. The adsorption capacity of MWNTs for isoliquiritin is higher than those for liquiritin and glycyrrhizic acid. MWNTs may be potentially applied to the separation and purification of isoliquiritins.
The adsorptions of three licorice derivatives including, isoliquiritin, liquiritin and glycyrrhizic acid on multi-walled carbon nanotubes(MWNTs), were investigated using UV and HPLC techniques. The effects of adsorption time, initial concentration, solution volume and its pH value on the adsorption of ciprofloxacin are examined. MWNTs have totally different adsorptive capacities toward the three main components. In the multi-component competitive adsorption examination, a noncompetitive adsorption process was observed. The adsorption capacity of MWNTs for isoliquiritin is higher than those for liquiritin and glycyrrhizic acid. MWNTs may be potentially applied to the separation and purification of isoliquiritins.
2011, 28(11): 1311-1316
doi: 10.3724/SP.J.1095.2011.00685
Abstract:
Bis(2-ethylhexyl) phosphoric acid(P204)/n-octanol reversed micelle system was prepared to extract L-synephrine in Citrus aurantium fruit crude extract. The extraction mechanism as well as influencing factors including the pH of the aqueous phase, water content(W0), surfactant concentration, and extraction time were studied. P 204/octanol reversed micelles was observed by AFM. The optimal extraction conditions determined via a series of experiments are as follows:aqueous phase pH=6.5, water content(W0)=15, surfactant concentration=0.08 mol/L, and extraction time=15 min. Under the optimized conditions, the one-time L-synephrine extraction rate reaches 68.0%. The mathematical model to fit the relationships of Lsynephrine extraction rate with aqueous phase pH and surfactant concentration is also discussed.
Bis(2-ethylhexyl) phosphoric acid(P204)/n-octanol reversed micelle system was prepared to extract L-synephrine in Citrus aurantium fruit crude extract. The extraction mechanism as well as influencing factors including the pH of the aqueous phase, water content(W0), surfactant concentration, and extraction time were studied. P 204/octanol reversed micelles was observed by AFM. The optimal extraction conditions determined via a series of experiments are as follows:aqueous phase pH=6.5, water content(W0)=15, surfactant concentration=0.08 mol/L, and extraction time=15 min. Under the optimized conditions, the one-time L-synephrine extraction rate reaches 68.0%. The mathematical model to fit the relationships of Lsynephrine extraction rate with aqueous phase pH and surfactant concentration is also discussed.
2011, 28(11): 1317-1322
doi: 10.3724/SP.J.1095.2011.00691
Abstract:
A new biosorbent from waste beer yeast was prepared by modification with triethylenetetramine and crosslinking with glutaraldehyde. The adsorption capability of the modified yeast for Hg(Ⅱ) in aqueous solution and the influence factors were studied. The results show that the optimized pH value was 2.8 at 25℃ and the adsorption process was carried out for 20 min. The maximum uptake capacities for Hg(Ⅱ) is 132.6 mg/g, which is about 6.3 times higher than that of the pristine yeast. With the modified yeast, the average removal rate for Hg(Ⅱ) in the wastewater is 100%. The kinetics for Hg(Ⅱ) adsorption followed the pseudo-second-order with R2=0.999 9. The adsorption process fitted the Langmuir model, indicating that it is a monolayer adsorption process.
A new biosorbent from waste beer yeast was prepared by modification with triethylenetetramine and crosslinking with glutaraldehyde. The adsorption capability of the modified yeast for Hg(Ⅱ) in aqueous solution and the influence factors were studied. The results show that the optimized pH value was 2.8 at 25℃ and the adsorption process was carried out for 20 min. The maximum uptake capacities for Hg(Ⅱ) is 132.6 mg/g, which is about 6.3 times higher than that of the pristine yeast. With the modified yeast, the average removal rate for Hg(Ⅱ) in the wastewater is 100%. The kinetics for Hg(Ⅱ) adsorption followed the pseudo-second-order with R2=0.999 9. The adsorption process fitted the Langmuir model, indicating that it is a monolayer adsorption process.
2011, 28(11): 1323-1330
doi: 10.3724/SP.J.1095.2011.00694
Abstract:
Two layered double hydroxides,[Ni4Al(OH)10]OH and [Co4Al(OH)10]NO3, were synthesized by chemical co-precipitation. The former was used as the active material and the latter as well as graphite were used as the conductive additives, respectively. The optimum ratio of the three materials in a positive electrode was estimated through the simplex-centroid design to improve the charge/discharge properties efficiently at a high current density. When the mass fractions of [Ni4Al(OH)10]OH,[Co4Al(OH)10]NO3 and graphite are 64.45%, 12.27% and 23.28%, respectively, the discharge capacity can retain 270.5 mA·h/g(88.7% of the maximum) after 200 cycles at a current density of 800 mA/g.
Two layered double hydroxides,[Ni4Al(OH)10]OH and [Co4Al(OH)10]NO3, were synthesized by chemical co-precipitation. The former was used as the active material and the latter as well as graphite were used as the conductive additives, respectively. The optimum ratio of the three materials in a positive electrode was estimated through the simplex-centroid design to improve the charge/discharge properties efficiently at a high current density. When the mass fractions of [Ni4Al(OH)10]OH,[Co4Al(OH)10]NO3 and graphite are 64.45%, 12.27% and 23.28%, respectively, the discharge capacity can retain 270.5 mA·h/g(88.7% of the maximum) after 200 cycles at a current density of 800 mA/g.
2011, 28(11): 1331-1336
doi: 10.3724/SP.J.1095.2011.00733
Abstract:
In a Britton-Robinson(BR) buffer solution of pH=10.0, Pd(Ⅱ) and carbendazim(CBZ) can form a 1:1 chelate complex. As a result, new spectra of resonance Rayleigh scattering(RRS), second-order scattering(SOS), and frequency doubling scattering(FDS) appears and their intensities are enhanced greatly. The maximum wavelengths of RRS, SOS and FDS are located at 309 nm, 606 nm and 310 nm, and their intensities are proportional to the concentration of CBZ in certain ranges. The methods have a high sensitivity with the detection limit of 7.1×10-9 g/mL for RRS method, 7.4×10-9 g/mL for SOS method and 1.07×10-8 g/mL for FDS method, respectively. Based on the above results, a new light scattering method for the determination of trace amounts of CBZ has been developed. The RRS method with the highest sensitivity is taken for the determination of carbendazim in celery and wettable powder. The results are consistent with those of the GB method. In addition, the reaction mechanism and the reasons of the enhancement of resonance light scattering are discussed.
In a Britton-Robinson(BR) buffer solution of pH=10.0, Pd(Ⅱ) and carbendazim(CBZ) can form a 1:1 chelate complex. As a result, new spectra of resonance Rayleigh scattering(RRS), second-order scattering(SOS), and frequency doubling scattering(FDS) appears and their intensities are enhanced greatly. The maximum wavelengths of RRS, SOS and FDS are located at 309 nm, 606 nm and 310 nm, and their intensities are proportional to the concentration of CBZ in certain ranges. The methods have a high sensitivity with the detection limit of 7.1×10-9 g/mL for RRS method, 7.4×10-9 g/mL for SOS method and 1.07×10-8 g/mL for FDS method, respectively. Based on the above results, a new light scattering method for the determination of trace amounts of CBZ has been developed. The RRS method with the highest sensitivity is taken for the determination of carbendazim in celery and wettable powder. The results are consistent with those of the GB method. In addition, the reaction mechanism and the reasons of the enhancement of resonance light scattering are discussed.
2011, 28(11): 1337-1339
doi: 10.3724/SP.J.1095.2011.00693
Abstract:
The Pt ion was extracted in the deactived catalyst for the hydrochlorination reaction of ethyne by acidic thiourea solution. The result shows that the extraction ratio is over 98% when the extraction phase volume ratio approaches 1, the concentration of thiourea is 0.2 mol/L and hydrochloric acid concentration is between 0.5 and 0.6 mol/L. Besides, there are some advantages such as keeping the organic phase composition. Organic phase can be reuses, and the ethyne conversion ratio is over 70% by using the fresh catalyst in the same organic phase.
The Pt ion was extracted in the deactived catalyst for the hydrochlorination reaction of ethyne by acidic thiourea solution. The result shows that the extraction ratio is over 98% when the extraction phase volume ratio approaches 1, the concentration of thiourea is 0.2 mol/L and hydrochloric acid concentration is between 0.5 and 0.6 mol/L. Besides, there are some advantages such as keeping the organic phase composition. Organic phase can be reuses, and the ethyne conversion ratio is over 70% by using the fresh catalyst in the same organic phase.
2011, 28(11): 1340-1342
doi: 10.3724/SP.J.1095.2011.00023
Abstract:
Enantiomers of amino acids and chiral drugs were separated by capillary zone electrophoresis using double(6-O-β-carboxy-methyl-1,4-maleic acid ester)-β-cyclodextrin(DOCB-β-CD) as chiral selector. The buffer solution used was 20 mmol/L phosphate. The influences of DOCB-β-CD concentration, background buffer pH value, temperature and applied voltage were investigated. Under the respective optimum condition, enantiomers separation of four kinds of DL-amino acids(Phenylalanine, Tryptophan, Tyrosine and Histidine) and two kinds of chiral drugs(rofecoxib and rosiglitazone) were attained with a clear separation from the baseline.
Enantiomers of amino acids and chiral drugs were separated by capillary zone electrophoresis using double(6-O-β-carboxy-methyl-1,4-maleic acid ester)-β-cyclodextrin(DOCB-β-CD) as chiral selector. The buffer solution used was 20 mmol/L phosphate. The influences of DOCB-β-CD concentration, background buffer pH value, temperature and applied voltage were investigated. Under the respective optimum condition, enantiomers separation of four kinds of DL-amino acids(Phenylalanine, Tryptophan, Tyrosine and Histidine) and two kinds of chiral drugs(rofecoxib and rosiglitazone) were attained with a clear separation from the baseline.
