Th- GSH : O 657 : A. ], Yoneyama Schlereth NADH [5 ], EG &G 273A Po2 tentiostat/ Galvanostat (USA). Th (Chroma. Co) GSH.

Transcription

1 EL ECTROCHEMISTR Y Vol 8 No 3 Aug 2002 : (2002) Th- GSH,,, (, ) 3 : ( GSH) (SAM) ( Th),, (DO) (AA) (100 ), mol L - 1 : ; ; ; ; : O 657 : A 20,, [1 2 (SAM) ],,, [3 ], [4 ], Yoneyama Schlereth NADH [5 ], NADH GSH SAM ( Th), 1 1 1, (25 2 ), Model RDE5, EG &G 273A Po2 tentiostat/ Galvanostat (USA) Th (Chroma Co) GSH ( EDC,Aldrich) DO (Sigma) AA m Al 2 O 3,, pirana ( H 2 SO 4 [6 ] : , Tel : (86-27) ; E- mail edu cn

2 H 2 O 2 30 % = 3 7) 30 min, 0 1 mol L - 1 H 2 SO V, (CV) (1 0 mmol/ L) 16 h, 0 1 mmol L Th DMSO + (1 1) 4 h ( mol L - 1 EDC),, GSH- Th SAM 1 GSH- Th SAM (CV),p H 1 12,, ( V) Th /, ( V) [6 Th ], 1 GSH- Th SAM p H GSH, CV GSH Fig 1 The CVs obtained on GSH- Th SAM Th, modified electrode depended on the Th ; p H value of solution (0 1 mol L - 1 H 2 SO 4 + NaOH),p H 1 12 ( solid), Th p H 3 01 ( dotted ) and p H 4 50 GSH SAM (dashed),respectively The potential 1, scanning rate,100 m Vs - 1, p H,, p H, GSH, 5 6 Th,, 1, Th Th, mol cm 2, Th ( mol cm 2 ) [3 ], GSH, GSH Th, Th 2 2 (DO) (1) DO mol/ L H 2 SO 4, DO AA, GSH- Th- SAM V V, DO AA V, ;

3 3 : Th- GSH 303, V DO AA, Th, Th, Th DO AA 2 GSH- Th SAM AA DO 3 GSH (A) GSH- Th SAM (B) CV Fig 2 The CVs obtained on Gsh- Th SAM modified electrode in 0 1 mol L - 1 H 2 SO 4 in the ab2 sence( solid) or in the presence of 0 1 mol L - 1 DO ( dashed ) rate,100 mv s - 1 The potential scanning AA DO CV Fig 3 The CVs obtained on (A) GSH SAM modified electrode in 0 1 mol L - 1 DO ( dotted) and (B) GSH- Th SAM modified electrode in 0 1 mol L - 1 PBS in the absence ( solid) or in the presence of 0 1 mol L - 1 AA ( dotted) or 0 1 mol L - 1 AA mol L - 1 DO ( dashed) The potential scanning rate,100 mv s - 1 DO,, V, V,, V, GSH SAM DO,, DO AA DO, (2) DO 3 (A) (B) AA DO, GSH SAM GSH-

4 Th SAM, Th- GSH,DO V,,, DO, AA, AA DO 4 (B) 2,DO p H, p H,, DO, p H 4 GSH- Th SAM AA, GSH, DO Fig 4 The square wave voltammgraph obtained on, the GSH- Th SAM modified electrode in 0 1 DO, 4 mol L - 1 PBS depended on the concentration of AA + DO,0 + 0, , , , , , , 100 AA DO mol L - 1,from up to down, respectively, mol/ L Potential scanning rate, 120 mv s - 1 ( step potential 2 0 mv,freauency 60Hz) and pulse amplitude was 25mV Inserting, the rela2 tionship between the cathodic peak currents and the concentration of DO Thionine- glutat hione Self-assembly Monolayer Modified Electrdoe and t he Quasi- reversible Response of Dopamine FAN G Cheng, L UAN Zheng, ZHAN G Wu- Ming,ZHOU Xing- Yao 3 ( Depart ment of Chemist ry, W uhan U niversity, W uhan , China) Abstract : Thionine was bound onto a glutathione monolayer self-assembled on the surface of a gold elect rode previously, t he elect rochemical characteristics of which were st udied It was found t hat dopamine had a quasi- reversible response and cat hodic characterstics peak could be used to de2 termine the concentration of dopamine in the range of mol L - 1 in the presence of a higher concent ration of ascorbic acid

5 3 : Th- GSH 305 Key words : Glutat hione, Thionine, Dopamine, Ascorbic acid, Monolayer Reference s : [1 ] Yang Sheng- Rong, Ren Si-Li, et al Structure and self-assembly mechanism of self-assembled monolayers [J ] Chem J Chinese Universities,2001,22(3) :470 [2 ] Ulman A Formation and structure of self-assembled monolayers[j ] Chem Rev,1996,96 :1 533 [3 ] Kontrec J, Svetlicic V The redox change and phase transformation in monolayer films of phenothiazines[j ] Electrochimica Acta,1998,43 :389 [ 4 ] Ruan Chuanmin, Yang Ru, et al A reagentless amperometric hydrogen peroxide biosensor based on covalent2 ly binding horseradish peroxidase and thionine using a thiol- modified gold electrode[j ] J Electroanal Chem, 1998,455 :121 [5 ] Ohtani M, Kuwabata S, Yoneyama H Electrochemical oxidation of reduced nicotinamide coenzymes at au electrodes modified with phenothiazine derivative monolayers[j ] J Electroanal Chem,1997,422 :45 [ 6 ] Xu Jing-J uan, Fang Huai- Qun, Chen Hong- Yuan The electrochemical characteristics of gold electrode modi2 fied by thionine covalently bound to self- assembled cysteamine monolayer and its electrocatalytic oxidation for ascorbic Acid[J ] Chem J Chinese Universities, 1997,18(5) :706