: A. 13 mmol L - 1.,. GSH

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1 ELECTROCHEMISTRY Vol 10 No 3 Aug 2004 : (2004) ,, (, ) : GSH (AB2PME),,GSH, CV AB2PME,GSH, 0 5 V, GSH AA UA GSH, GSH,GSH AB2PME : ; ; ; : O 646 : A (reduced glutathione, N2(N2L2 2glutamyl2L2cysteinyl) glycine, GSH),, 13 mmol L - 1, [1 GSH ], GSH [2 5 ], GSH (2SH), (oxidized glutathione, GSSG),, GSH GSH, [6,7, GSH ], GSH, GSH [4,5 ], : ; : ,Tel : (86227) edu cn ( ) China Academic Journal Electronic Publishing House All rights reserved

2 3 : V(vs SCE), (AA) (UA), GSH /, [8 ], 2SH GSH, GSH GSH Sigma, ph = mol NaH 2 PO mol/ L Na 2 HPO 4 ( PBS) GSH PBS 1 2 (acetylene black, AB, 50 m 2 / g), [9 ], 100 m( 90 m) 60 m( 70 m ) Pt 0 5 mm, 4mm (SCE), 1 3 (CV) CHI625 ( ), GSH : AB2PME 3 mmol L - 1 GSH, V V, CV, PBS CV, GSH GSH CV 1 4 [10 ] 1 1 ( V/ V), 0 1 mol L - 1 PBS 5 2 [3,5 ] 2 1 GSH 1 1mmol L - 1 GSH CV, V,GSH ( la) ( lb),,,, GSH V(vs SCE,pH = 7 0) [7 ] 1a,,, GSH GSH (2SH), 2 2 GSH AB2PME 2 AB2PME GSH PBS CV China Academic Journal Electronic Publishing House All rights reserved L - 1

3 mmol L - 1 GSH CV Fig 1 The CV curves obtained with Pt and GC electrode in PBS containing 1mmol L - 1 GSH ( : GSH, :PBS, scan rate :100 mv/ s) a Pt electrode(dia :0 5 mm),b GC electrode(dia :4 mm),, V, GSH ( ), GSH, ( GSH ),, 0 5 V GSH 3 AB2PME 2 mmol L - 1 GSH, IE 2 AB - PMA GSH PBS CV GSH, 20nA GSH Fig 2 The oxidation current peaks of GSH ob2 D = cm 2 s - 1[11 ], tained with AB2PME electrode in PBS containing various concentration of GSH : I L = 4 nfdcr ( dia of the electrode : 100 m, scan rate : 100 mv/ s) concentration of 1 GSH/ mmol L - 1 : 0) 0, 1) 0 113, 2) 0 351, 3) 0 657, 4) 1 02, 5) , the inset : the relationship between peak : currents and GSH concentration GSH - e GS + H + (1) ads - e GS + HSG solution ads GSHSG (2) GSHSG ϖ GSSG+ H + (3) China Academic Journal Electronic Publishing House All rights reserved

4 3 : AA UA GSH 4 5 AB2PME AA UA 1 mmol L - 1 GSH CV, AA GSH, GSH UA, 130 mv 250 mv AA,,, GSH ( 4) UA GSH, UA 3 AB - PME 2 mmol L - 1 GSH, GSH ( 5), Fig 3 The steady state polarization curve obtained AA UA GSH with AB - PME electrode in PBS containing GSH AB2PME 10 scan rate : 1 mv/ s) mmol L - 1 GSH (dia of the electrode :60 m,, CV 6 6, V GSH( ), GSH, 4 AB2PME 1 mmol L - 1 GSH 5 AB2PME 1 mmol L - 1 GSH AA 1 mmol L - 1 GSH CV UA 1 mmol L - 1 GSH CV Fig 4 The oxidation current peaks obtained with AB2PME Fig 5 The oxidation current peaks obtaind with AB - PME electrode in PBS containing 1 mmol L - 1 GSH and electrode in PBS containing 1 mmol L - 1 GSH and various excess of AA Concentration of AA/ mmol L - 1 : 0) 0, 1) 0 1, 2) 0 2, 3) 0 3, 4) 0 4, 5) 0 5 (dia of the electrode :100 m,scan rate : 100 mv/ s) various excess of UA Concentration of UA/ mmol L - 1 : 0) 0 01, 1) 0 1, 2) 0 02, 3) 0 03, 4) 0 04, 5) 0 05 ( dia of the electrode : 100 m, scan rate : 100 mv/ s) China Academic Journal Electronic Publishing House All rights reserved

5 , ( 2), V, UA UA [8 AB ], AA, [8, AB ], GSH [ GSH] = 10 C I I P1 I P1 GSH P ( 6 1), C I P GSH, GSH 6, 6 AB2PME CV 1) 10 GSH 2 4 mmol L ( 2mL),2) 1 15 L 40 mmol L - 1 GSH, GSH Fig 6 The oxidation current peaks obtained with AB2, CV PME electrode in human erythrocyte solution curve 1) 10 fold diluted solution of human AB2PME, GSH erythrocyte, 2) after addition of 15 L 40,, mmol L - 1 GSH into 1), 0 5 V CV GSH GSH, AA UA GSH AB2PME, GSH The Electrochemical Behavior and Determination of GSH at the Powder Microelectrode CHEN Jian 3, HE Zhong2yu, CHA Chuansin, LIU Huan ( College of Chemistry and Molecular Science, Wuhan University, Wuhan , China) Abstract : In this paper, the electrochemical behavior of GSH at the surface of platinum( Pt) elec2 trode, glass carbon ( GC) electrode and acetylene black packed powder microelectrode (AB2PME) was studied It was found that the electrochemical oxidations of GSH at both Pt and GC electrode were highly irreversible No current peak or current plateau could be observed from the CV curves The direct elec China Academic Journal Electronic Publishing House All rights reserved

6 3 : 259 tro2oxidation of GSH at carbon surface was achieved by using the PME technique In this case, the appar2 ent reversibility of GSH oxidation was enhanced significatly The overpotential of GSH oxidation was re2 duced to 0 5 V at the surface of AB2PME compared with that obtained with Pt and GC electrodes The exhaustive electrolysis of GSH within the micro2cavity of the PME can be achieved As a result, the peak currents obtained with AB2PME were proportional to GSH concentration The interference caused by ascorbic acid and uric acid was eliminated completely by employing AB2PME electrode The concen2 tration of GSH in human erythrocyte was determined by employing the AB2PME technique and using the method of internal standard addition The steady state polarization curve of GSH was obtained with the AB2PME electrode The number involved in the electrochemical oxidation of GSH was calculated as 1 by using the value of I L Key words : Powder microelectrode, GSH, Antioxidant, Ascorbic acid,uric acid Reference s : [1 ] Staal F J T, Ela S W, Roederer M, et al Glutathione deficiency and human immunodeficiency virus infection[j ] The Lancet, 1992,339 :909 [ 2 ] Compagnone D, Federici G,Scarciglia L,et al Amperometric glutathione electrodes [J ] Biosensors &Bioelectronics, 1993,8 :257 [3 ] Stephen A W,John P H, Brian J B Development of an amperometric assay for the determination of reduced glu2 tathione,using glutathione peroxidase and screen2printed carbon electrodes chemically modified with cobalt phthalo2 cyanine[j \ Electroanalysis, 1992,4 :299 [4 ] Zhang S,Sun W L,Zhang W,et al,determination of thiocompounds by liquid chromatography with amperometric de2 tection at a Nafion/ indium hexacyanoferrate film mokified electrode[j ] Analytica Chimia Acta, 1999,386 :21 [5 ] Stephen A W,John P H, Brian J B Development of an improved carbon electrode chemically modified with cobalt phthalocyanine as a re2usable sensor for glutathione[j ] Analyst, 1989,114 :1563 [6 ] Jin W R,Zhan X, Xian L Mechanism of the electrochemical reaction of glutathione at a mercury electrode[j ] Elec2 troanalysis, 2000,12(11) :858 [7 ] Stricks W,Kolthoff I M, Polarography of glutathione[j ]J Am Chem Soc,1952,74 :4646 [8 ] Xiao L F, Chen J, Cha C S Elimination of theinterference of ascorbic acid in the amperometric detection of biomolecules in body fluid samples and the simple detection of uric acid in human serum and urine by using the pow2 der microelectrode technique[j ] J Electroanal Chem, 2000,495 :27 [9 ] Cha C S, Li C M, Yang H X, et al Powder microdlectrodes[j ] J Electroanal Chem,1994,368 :47 [10 ] Chen J,Stoecklein W, Scheller F W,et al Electrochemical determination of human hemoglobin by using ferrocene carboxylic acid modified carbon powder microelectrode[j ] Analytical Letters, 2003,36(9) :2049 [11 ] Jin W R, Chen H F, A new method of determination of diffusion coefficient using capillary zone electrophoresis (peak2height method) [J ] Chromatographia, 2000,52 : China Academic Journal Electronic Publishing House All rights reserved