In this paper, an amperometric acetylcholinesterase(ACh E) biosensor for quantitative determination of carbaryl was developed. Firstly, the poly(diallyldimethy-lammonium chloride)-multi-walled carbon nanotubes-graphen...In this paper, an amperometric acetylcholinesterase(ACh E) biosensor for quantitative determination of carbaryl was developed. Firstly, the poly(diallyldimethy-lammonium chloride)-multi-walled carbon nanotubes-graphene hybrid film was modified onto the glassy carbon electrode(GCE) surface, then ACh E was immobilized onto the modified GCE to fabricate the ACh E biosensor. The morphologies and electrochemistry properties of the prepared ACh E biosensor were investigated by using scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. All variables involved in the preparation process and analytical performance of the biosensor were optimized. Based on the inhibition of pesticides on the ACh E activity, using carbaryl as model compounds, the biosensor exhibited low detection limit, good reproducibility and high stability in a wide range. Moreover, the biosensor can also be used for direct analysis of practical samples, which would provide a new promising tool for pesticide residues analysis.展开更多
The reversed micelles were formed with cationic cetyltrimethylammonium bromide (CTAB) as surfac
tant and n-hexanol as cosolvent in the CTAB (50mmol.L-1)/hexanol (15% by volume)/hexane system. Cibacron
Blue 3GA (CB) a...The reversed micelles were formed with cationic cetyltrimethylammonium bromide (CTAB) as surfac
tant and n-hexanol as cosolvent in the CTAB (50mmol.L-1)/hexanol (15% by volume)/hexane system. Cibacron
Blue 3GA (CB) as an affinity ligand in the aqueous phase was directly introduced to the reversed micelles with
electrostatic interaction between anionic CB and cationic surfactant. High molecular weight (Mr) protein, yeast
alcohol dehydrogenase (YADH, Mr = 141000) from baker's yeast, has been purified using the affinity reversed
micelles by the phase transfer method. Various parameters, such as CB concentration, pH and ionic strength, on
YADH forward and backward transfer were studied. YADH can be transferred into and out from the reversed mi
celles under mild conditions (only by regulation of solution pH and salt concentration) with the successful recovery
of most YADH activity. Both forward and backward extractions occurred when the aqueous phase pH＞pI with
electrostatic attraction between YADH and CTAB. The recovery of YADH activity and purification factor have
been improved with addition of a small amount of affinity CB. The recovery of YADH activity obtained was ～99%
and the purification factor was about 4.0-fold after one cycle of full forward and backward extraction. The low ionic
strength in the initial aqueous phase might be responsible for the YADH transfer into the reversed micellar phase.展开更多
The solvent extraction of KAu(CN)2 from alkaline solution by quaternary ammonium salts (trialkylmethylammonium chloride or cetyltrimethylammonium bromide) waw investigated by means of ^198Au radioactive tracer method....The solvent extraction of KAu(CN)2 from alkaline solution by quaternary ammonium salts (trialkylmethylammonium chloride or cetyltrimethylammonium bromide) waw investigated by means of ^198Au radioactive tracer method. Various parameters,such as the gold (I) concentration in aqueous phase,the modiffer,emulsifiation at the interface of two phases, and phase ratio used in the extraction of gold (I) were studied. The results demonstrate that almost all gold (I) in the aqueous phase was practically extracted into the organic phase. The water content in the organic phase decreased significantly with increase of gold (I) concentration using long chain alcohol as modifier,in contrast with the system with tributyl phosphate (TBP) as modifier. Emulsification at the interface of two phases decreases with an increase of modifier concentration in the organic phase or with the addition of a small amount of lysozyme into the aqueous phase. The method with ^198Au tracer can be directly used to determine the Au(I) concentration both in aqueous and organic phases, which is especially suitable for the low concentration of Au(I).展开更多
基金supported by the National Natural Science Foundation of China(No.30972055,31101286)Agricultural Science and Technology Achievements Transformation Fund Projects of the Ministry of Science and Technology of China(No.2011GB2C60020)Shandong Provincial Natural Science Foundation,China(No.Q2008D03)
文摘In this paper, an amperometric acetylcholinesterase(ACh E) biosensor for quantitative determination of carbaryl was developed. Firstly, the poly(diallyldimethy-lammonium chloride)-multi-walled carbon nanotubes-graphene hybrid film was modified onto the glassy carbon electrode(GCE) surface, then ACh E was immobilized onto the modified GCE to fabricate the ACh E biosensor. The morphologies and electrochemistry properties of the prepared ACh E biosensor were investigated by using scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. All variables involved in the preparation process and analytical performance of the biosensor were optimized. Based on the inhibition of pesticides on the ACh E activity, using carbaryl as model compounds, the biosensor exhibited low detection limit, good reproducibility and high stability in a wide range. Moreover, the biosensor can also be used for direct analysis of practical samples, which would provide a new promising tool for pesticide residues analysis.
基金the National Natural Science Foundation of China (No. 29836130).
文摘The reversed micelles were formed with cationic cetyltrimethylammonium bromide (CTAB) as surfac
tant and n-hexanol as cosolvent in the CTAB (50mmol.L-1)/hexanol (15% by volume)/hexane system. Cibacron
Blue 3GA (CB) as an affinity ligand in the aqueous phase was directly introduced to the reversed micelles with
electrostatic interaction between anionic CB and cationic surfactant. High molecular weight (Mr) protein, yeast
alcohol dehydrogenase (YADH, Mr = 141000) from baker's yeast, has been purified using the affinity reversed
micelles by the phase transfer method. Various parameters, such as CB concentration, pH and ionic strength, on
YADH forward and backward transfer were studied. YADH can be transferred into and out from the reversed mi
celles under mild conditions (only by regulation of solution pH and salt concentration) with the successful recovery
of most YADH activity. Both forward and backward extractions occurred when the aqueous phase pH＞pI with
electrostatic attraction between YADH and CTAB. The recovery of YADH activity and purification factor have
been improved with addition of a small amount of affinity CB. The recovery of YADH activity obtained was ～99%
and the purification factor was about 4.0-fold after one cycle of full forward and backward extraction. The low ionic
strength in the initial aqueous phase might be responsible for the YADH transfer into the reversed micellar phase.
基金Supported bv National Natural Science Foundation of China (No. 39730160, No. 20023005).
文摘The solvent extraction of KAu(CN)2 from alkaline solution by quaternary ammonium salts (trialkylmethylammonium chloride or cetyltrimethylammonium bromide) waw investigated by means of ^198Au radioactive tracer method. Various parameters,such as the gold (I) concentration in aqueous phase,the modiffer,emulsifiation at the interface of two phases, and phase ratio used in the extraction of gold (I) were studied. The results demonstrate that almost all gold (I) in the aqueous phase was practically extracted into the organic phase. The water content in the organic phase decreased significantly with increase of gold (I) concentration using long chain alcohol as modifier,in contrast with the system with tributyl phosphate (TBP) as modifier. Emulsification at the interface of two phases decreases with an increase of modifier concentration in the organic phase or with the addition of a small amount of lysozyme into the aqueous phase. The method with ^198Au tracer can be directly used to determine the Au(I) concentration both in aqueous and organic phases, which is especially suitable for the low concentration of Au(I).
