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1 EL ECTROCHEMISTR Y Vol 7 No 3 Aug 2001 : (2001) , 2 1 3, ( ; 2, ;3, ) : Au( ) Cu( ), Au ( ) Cu ( ) Au( ) Cu( ), Au ( ) g/ ml Cu( ) 2 10 ng/ ml 20 ng/ ml 0 5 ng/ ml,8 RSD 3 % : ; ; ; ; : O : A Au( ) Cu ( ), [1,2 ] [3,X - ], [4 ] [5 ] [6,7 ] Au ( ) Cu ( ) Au ( ) Cu ( ) ; 8511A ; T YPE 3086X2Y ; METTL ER TOL EDO 320 p H 1 2 ;CuCl 2 ; KCl ; ( A R : ; : :

2 ), DO1 ( DO1 ) :0 25 ( 6 mm 1 5 mm) ( ) DO1, DO1, mol/ L HCl p H = 1 5 KCl ; N 2 O 2 ; 0 70 V (vs S C E, ) 10 min ( 5 min), 1 min 30 mv/ s( 50 mv/ s) 0 70 V V, Au( ), V 10 min ( 5 min), 1 min 30 mv/ s 50 mv/ s V 0 70 V, Cu ( ) ) : (a) (b),,,,, AuCl - 4 Au ( ) DO1, Au ( ) Au ( ) 1 Au( ) Cu( ) Fig 1 Two-waystripping voltammetric curves of a solution of the Au( ) and Cu ( ) at DO1 modified electrode 2) Au ( ) Cu ( ) Concentration : 1 Au( ) 5 g/ ml ; 2 Cu ( ) 60 ng/ L Pre-concentrated time : 5 min, Scan rate : 50 mv/ s, (p H 1 DO1, = 1 5 HCl) Au ( ) Cu ( )

3 3 : 341 Au ( ) V, Cu V,, 2 2 1) DO1 Au ( ) DO1 Au ( ) 2 5 ; [6 1 6 % ] 1 6 %DO1 2) 1 :0 25 3) : 1 Au( ) Tab 1 The relationship between I pk of Au( ) cathodic stripping and anodic electrolyze voltage Deposition voltage/ V Peak current/ A Concentration :Au( ) 5 g/ ml ; Cu( ) 60 ng/ ml Deposition time : 5 min, Scanning rate :50 mv/ s 1 ( ) ( 1 ), 0 70 V 2, Au ( ) Cu ( ) H + Cu V 2 Cu( ) Tab 2 The relationship between I pk of Cu anode stripping and cathodic electrolyze voltage Depositio voltage/ V Peak current/ A Concentration :Au( ) 3 g/ ml ; Cu( ) 0 15 g/ ml Deposition time : 5 min, Scanning rate 50 mv/ s

4 ) p H 3 p H, p H, Au ( ) Cu( ) p H 1 04 DO1 p H Au( ) Cu( ) p H Tab 3 The relationship between l pk and the p H of the solution p H I pk / A Au( ) Cu( ) Concentration :Au( ) 3 g/ ml ; Cu( ) 0 15 g/ ml Deposition time : 5 min, Scsnning rate :50 mv/ s 2 3 Au ( ) Cu ( ) 1) 2 DO1 Au ( ) Cu ( ) Au( ) g/ ml,cu( ) 2 10 ng/ ml ) 8 Au ( ) Cu ( ), Au ( ) RSD 2 44 %,Cu RSD 2 86 % Au ( ) Cu ( ) 3) 3 Au ( ) 20 ng/ ml,cu( ) 0 5 ng/ ml, Au ( ) 4), Au ( ) 1 g/ ml Cu ( ) 12 ng/ L,500 g/ ml Fe 3 + Co 2 + Ni 2 + Zn 2 + Cd 2 + Cr 3 + Pb g/ ml Ag + Hg 2 +,5 g/ ml Pd 2 + Au ( ), Cu Au ( ) Cu ( ) 3 Au ( ) Cu ( )

5 3 : Au( ) Cu( ) Fig 2 Liner2dependence between I pk and Au ( ) or Cu ( ) concentration 1 : Au ( ), ng/ ml 2 : Cu ( ), 2 10 ng/ ml Deposition time :10 min Scan rate :30 mv/ s Fig 3 Two-way stripping voltammetric curves of DO1 modified electrode in asolution of Au( ) and Cu ( ) 1 Au( ) 20 ng/ ml ; 2 Cu( ) 5 ng/ ml Deposition time 5 min Scan rate : 50 mv/ s, (p H = 1 5 HCl) Simultaneous Determination of Gold ( ) and Copper ( ) wit h Two- way Stripping Voltammetry HU Rong-zong 1, WEI Dong-ping 2, WEI Guang 1, L IU Yue-ying 3 (1 Chem Dept, S tate Key L ab f or the Phys Chem of the Solid S urf ace, Xiamen U niversity, Xiamen , China ; 2 Chem Dept and Chemical Engineering, Guangxi N ational College, N anning , China ; 3 B iolo Dept, Xiamen U niversity, Xiamen , China) Abstract : A novel Two- way St ripping Voltammet ry met hod for simultaneous determination of Au 3 + and Cu 2 + was reported in this paper Because of the strongly electrostatic attraction of car2 bon paste electrode towards Au ( ) ion at positive potential and t he biochemical cont ribution of Gram-positive bacteria strain DO1, the ion can be determined by cathodic stripping voltammetry At the same time, Cu( ) is reduced readily under the catalysis of ultra-fine gold particles, there2 after it can be determined by anode st ripping voltammet ry There is no interference between t he determination of Au 3 + and Cu 2 + A perfect liner relationship between the concentrations of cations and peak heights in the range of g/ ml (Au 3 + ) and 2 10 ng/ ml (Cu 2 + ) re2 spectively were observed The detection limit is 20 ng/ ml for Au ( ), and 0 5 ng/ ml for Cu ( ) The relative standard deviation of the response to 5 g/ ml Au 3 + and 60 ng/ ml Cu 2 + are

6 less than 3 % Key words : Two- way st ripping voltammet ry, Bacteria modified elect rode, Gold, Copper, Carbon paste Reference s : [ 1 ] Zhou Jimeng, Zhou Dehai Determination of trace Tl( ) Au( ) Cu( ) by enriching them with P- DB18C6 and atomic absorpion spectrophotometry[j ] Chemical Research and Application (in Chinese),1999,11 (2) : [ 2 ] Wang Tongju, Wang Anhua, Xu Meizhi Simultaneous determination of gold, silver and copper in carbon by flame perchloric acid as oxidizer[j ] Metallurgical Analysis(in Chinese),1999,19 (5) :52 53 [3 ] Chen Yongjun, Zhan Xiuchun,Zheng Miaozi Determination of gold,silver,copper and znic in gold standard samples by mylar film- XRF[J ] Rock and Mineral Analysis(in Chinese),1994,13 (3) : [4 ] Moustafa M E, Mabrouk E M, Dessouki H A, et al Spectrophometric microdetermination of copper ( ), silver ( ), and gold( ) using azastyrene schiff bases[j ] MicrochemJ 1991,44 : [5 ] J yotsna Shukla, Pitre K S Electrochemical trace analysis of gold in orc[j ] Analyst 1996,121 :79 81 [6 ] Hu Rongzong, Xu Hao, Fu Jinkun, et al Electrochemical determination of trace amounts of gold( ) by ca2 thodic stripping voltammetry using carbon paste electrode modified with bacteria[j ] Electrochemistry(in Chi2 nese), 1998,4 (3) : [7 ] Hu Rongzong, Ruan Yuanping, Xu Hao, et al Preparation and application of gold-film on the surface bacte2 rial- modified carbon paste electrode[j ] Electrochemistry(in Chinese),1999,5 (2) : [8 ] Hu Rongzong, Zhang Weide, Liu Yueying, et al Determination of trace amounts of gold ( ) by cathodic stripping voltammetry using a bacteria- modified carbon paste electrode[j ] Anal Commun 1999,36 : [9 ] Peng Tuzhi, Wang Guoshun, Zhu Peilin Electrostatic adsorption of gold ( ) on carbon paste electrode and its voltammetric determination[j ] Chinese Journal of Applied Chemistry(in Chinese), 1992,9 (2) :76 78

1. 5 : : O : A. (Aloe), Vol. 7 No. 4 Nov EL ECTROCHEMISTR Y : (2001) , ) 0. 1 mol/ L HAc (p H 2. 89) . 1.

1. 5 : : O : A. (Aloe), Vol. 7 No. 4 Nov EL ECTROCHEMISTR Y : (2001) , ) 0. 1 mol/ L HAc (p H 2. 89) . 1. 7 4 2001 11 EL ECTROCHEMISTR Y Vol 7 No 4 Nov 2001 :1006-3471 (2001) 04-0487- 07 1 5 3,,, (, 350004) : 0 1 mol/ L HAc (p H 2 89),, I p E p p H 1 5-0 80 V (vs SCE), E p - 0 38 V, I p 2 0 10-7 8 0 10-6 mol/