) ; GSP ) ;PXD g, 100 ml

30 (FENXI HUAXUE) 10 2002 10 Chinese Journal of Analytical Chemistry 1163 1167 3 3 3 (, 225002) PVC, 1. 0 10-4 1. 0 10-8 molπl, 58. 6 mvπdecade ; 2. 5 10-9 molπl, 2 3,,,,, 1, PVC Pretsch 1, EDTA,, 5 10-12 molπl Qin Pretsch 2, K +, Na +, Ca 2 + Mg 2 + Pretsch 3,4 Bakker 5 PVC, : ;, 2 2,, 6,7 5 10-7 molπl 1 10-6 molπl 2 3 2 2. 1 2. 1. 1 PXJ21B ( ) ;PXD212 ( ) ; GSP280204 ; 801 ( ) ;WHT210A ( ) 2. 1. 2 (, ) (, ),, 2. 2 2. 2. 1 40. 8 mg, 50 ml, 100 ml, 1. 0 10-3 molπl 2. 2. 2 ( TISAB) 9 TISAB 1 molπl HAc + 2 molπl NaAc + 1 molπl NaCl ( I 3) 10 100 I 0. 3 I 0. 03 2. 3 PVC 9 2. 3. 1 0. 5332 g, 100 ml 1. 0267 g 2001211218 ;2002206205 3 3

1164 30 150 ml,, Cl -, 2,50, 2 10 2. 3. 2 PVC 2 0. 2 mg, 1. 36 g, 0. 6 g PVC 7 ml, 5 cm 2 0. 01 % 2 2 % 1 % 0. 1 % 0. 001 % 2. 3. 3 WHT210A 2. 3. 4 Ag, AgCl 0. 01 molπl NaCl + 5 10-4 molπl PVC S. C. E 2. 3. 5 0. 01 molπl NaCl + 5 10-4 molπl PVC 1. 0 10-4 molπl 30 min ( - 15 mv),, ( - 15 mv),, 3, PVC PVC, 11 13,, PVC, 30 min 2, - 15 mv,, 1 PVC Fig. 1 The effect of active substance concentration in polyvinyl chloride ( PVC) membrane on the electrodes 3. 1 performance PVC 2 1. 0. 001 % ; 2. 0. 01 % ; 3. 0. 1 % ;4. 1 % ;5. 2 %, 1 1 1 Table 1 Influence of active substance concentration in membrane on the electrode performance Membrane concentration ( wπw %) 0. 001 2. 5 10-8 1. 8 10-4 55. 2 2. 5 10-9 0. 01 1. 0 10-8 1. 8 10-4 58. 7 2. 5 10-9 0. 1 2. 5 10-8 2. 2 10-4 60. 8 1. 0 10-8 1. 0 2. 5 10-7 2. 2 10-4 78. 1 2. 0 10-7 2. 0 2. 5 10-6 1. 8 10-4 89. 8 6. 3 10-7,,,,,, 0101 %,,

10 : 1165 3. 2 0. 28 0. 16 0. 07 mm, 0101 %, 0. 16 mm ( 2) 2 (20, 0. 01 %) Table 2 Influence of the membrane thickness on the electrode performance(20, active substance concentration : 0. 01 %) Membrane thickness (mm) 0. 28 5. 8 10-8 1. 0 10-4 4. 3 10-9 58. 8 0. 16 1. 0 10-8 1. 0 10-4 2. 5 10-9 59. 8 0. 07 3. 7 10-8 1. 0 10-4 3. 5 10-9 61. 1 3. 3 AgΠAgCl, (a) 0. 01 molπl NaCl ; (b) 0. 01 molπl NaCl 1. 0 10-7 molπl ; (c) 0. 01 molπl NaCl 5. 0 10-6 molπl ; (d) 0. 01 molπl NaCl 5. 0 10-4 molπl ; (e) 0101 molπl NaCl 5. 0 10-4 molπl :a d, (d) 0. 01 molπl NaCl 5. 0 molπl,, 0. 01 molπl NaCl 5. 0 10-4 molπl, 1. 3 10-8 molπl, 56. 6 mvπdecade,,, 3. 4 4 molπl (TISAB) 10 0. 4 molπl TISAB, 100 0. 04 molπl TISAB,,0. 4 molπl TISAB ( I 0. 3), ( 3) 3 Table 3 Effect of different supporting electrolyte concentration on electrode performance Supporting electrolyte 4 molπl TISAB 2. 5 10-7 1. 0 10-4 54. 5 2. 5 10-8 0. 4 molπl TISAB 1. 0 10-8 1. 0 10-4 58. 5 2. 5 10-9 0. 04 molπl TISAB 2. 5 10-7 1. 0 10-4 52. 5 2. 5 TISAB :total ion strength adjustment buffer 3. 5 10-7 10-8 molπl, 30 min ; 10-7 molπl, 2 min 3. 6 PVC,,, 8, 4 TISAB, 20 K ij, 6,7 3. 7 2. 5 10-6 2. 5 10-8 molπl, 6, ( - 15 mv), 5 (25 ), 1. 25 10-7 molπl 4 h, 0. 5 mv, - 15 mv,, 10-8 10-4

1166 30 4 Table 4 Selectivity coefficients Interferent K ij Interferent K ij KNO 3 NH 4 Cl Ca (NO 3 ) 2 Mg(NO 3 ) 2 Oxalic acid Tartaric acid Citric acid Benzoic acid Bendazol Lidocaini hydrochloride 1. 7 10-6 Dihydralazine sulfate 1. 4 10-6 Procaini hydrochloride 6. 0 10-7 Clonidine hydrochloride 6. 7 10-7 Atropini sulfate 1. 4 10-5 Ephedrini hydrochloride 1. 1 10-5 Ambroxol hydrochloride 7. 0 10-6 Theophylline 2. 5 10-5 2. 3 10-4 6. 3 10-4 1. 3 10-5 1. 6 10-3 4. 5 10-5 3. 1 10-4 1. 6 10-5 VB 6 2. 4 10-3 3. 6 10-3 Urea 1. 8 10-5 2. 0 10-4 VC 1. 6 10-3 5 Table 5 Reproducibility of electrode Concentration Potential (mv) Average value (mv) Standard deviation 2. 5 10-8 2. 5 10-7 2. 5 10-6 15. 2 15. 4 15. 1 14. 8 14. 7 15. 0 76. 2 76. 3 76. 1 75. 8 76. 0 76. 0 133. 3 133. 4 133. 2 132. 9 133. 1 133. 0 15. 0 76. 1 133. 2 0. 3 0. 2 0. 2 3. 8 0. 204 g 10. 2 g,, 95. 9 % 109. 3 % ( 6) 6 Table 6 Recovery test Added( g) Found( g) Recovery( %) Added( g) Found( g) Recovery( %) 0. 204 0. 204 100. 0 4. 08 4. 46 109. 3 1. 02 0. 978 95. 9 10. 2 10. 7 104. 9 2. 04 2. 13 104. 4 References 1 Sokalski T, Ceresa A, Zwickl T, Pretsch E. J. Am. Chem. Soc., 1997,119 :11347 11348 2 Qin W, Zwickl T, Pretsch E. Anal. Chem., 2000,72 :3236 3240 3 Sokalski T, Zwickl T, Bakker E, Pretsch E. Anal. Chem., 1999, 71 :1204 1209 4 Morf W E, Badertscher M, Zwickl T, De Rooij N F, Pretsch E. J. Phys. Chem. B, 1999, 103 :11346 11356 5 Mathison S, Bakker E. Anal. Chem., 1998, 70 :303 309 6 Shen Guoli ( ),Yao Shouzhuo ( ),Jiang Xiaohui ( ), Wu Weiqing( ). Chinese J. Anal. Chem. ( ),1983,17 (7) :481 484 7 Chi Hua ( ),Zhou Tonghui ( ). Acta Pharmaceutica Sinica ( ),1983,18 (4) :278 284 8 Bakker E, Pretsch E, Buhlmann P. Anal. Chem., 2000, 72 :1127 1133 9 Leng Zongzhou( ),Hu Xiaoya( ). Chinese J. Anal. Chem. ( ), 1991,19 (11) :1301 1304 10 Shen Guoli ( ),Liao Daiqing( ). Chinese J. Pharm. Anal. ( ),1984, 4 (4) :200

10 : 1167 11 Yao Shouzhuo ( ),Zhu Anxin ( ),Nie Lihua ( ). Chinese J. Pharm. Anal. ( ), 1986, 6 (4) : 205 12 Yao Shouzhuo ( ),Shen Guoli ( ),Wu Hailong( ). Chinese J. Pharm. Anal. ( ),1984,4 (5) : 281 13 Hu Xiaoya( ), Leng Zongzhou( ). J. Yangzhou Teachers College ( ),1988,8 (1,2) :56 A Ne w Method for Improving Detection Limit of Berberine Polyvinyl Chloride Ion Selective Electrode Jin Gendi, Hu Xiaoya 3, Leng Zongzhou, Wang Chengyin ( Department of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002) Abstract The detection limit of berberine polyvinyl chloride (PVC) ion selective electrode is determined chiefly by dissolution of active substance in water from PVC membrane and transfer of ion determined in PVC membrane from internal reference solution to external solution. In order to improve the detection limit, we used clonidine2 tetraphenylborate as ion2pair complex for the determination of berberine with internal reference solution of NaCl containing clonidine, and a satisfied result was obtained with a linear range of 1. 0 10-4 1. 0 10-8 molπl, average slope of 58. 6 mvπdecade and detection limit of 2. 5 10-9 molπl which was 2 3 orders of magnitude lower than that of previous reports. This method shows higher selectivity than that of other reports, and more true and reliable selectivity coefficients can be measured. Satisfactory recoveries are acquired by the standard addition method. Keywords Ion selective electrode, clonidine, berberine The electrode also shows stable and good reproducibility. (Received 18 November 2001 ; accepted 5 June 2002) 12 ( Euroanalysis - 12), 12 (Euroanalysis - 12) 2002 9 8 13 47 446 40 17 ; 3 84, 9, 3 9 : (1) ; (2) ; (3) ; (4) ; (5) ; (6) ; (7) ; (8) ; (9), 394 12, : (25 ) ; (20 ) ;,(10 ) ; (31 ) ; : (24 ) (54 ) ; (29 ) ; (89 ) (31 ) ; (26 ) ; (47 ) ; : (18 ),, 1972, 11 12 13 ( Euroanalysis ) 2004 Salamanca,, 50,