M. Stoytcheva,1,* R. Zlatev,1 Z. Velkova,2 B. Valdez,1 M. Ovalle 1
1Universidad Autónoma de Baja California, Instituto de Ingeniería, Mexicali 21280, Baja California, México
2University of Food Technologies, Department of Inorganic and Physical Chemistry, Plovdiv 4002, Bulgaria
Received 25 April 2008; accepted 18 October 2008
Abstract
]]> The goal of this work is the evaluation of the analytical characteristics of the determinations performed using glucose oxidase and acetylcholinesterase based electrochemical sensors, developed applying original or optimized conventional methods of enzyme immobilization. It was found that the sensitivity of glucose determination, for example, varies from 0.048 to 3.36 mA L mol-1 cm-2 and the response time of the glucose oxidase based sensors – from 5 to 30s, according to the method of the bioreceptor immobilization. The sensitivity of the analysis is affected from the activity of the immobilized biocomponent, from the composition of the solution (concentration of the substrate, of the mediator and of the inhibitor), and from the experimental conditions (pH, temperature, agitation), as well as from the kinetic parameters of the studied process. It was found that the immobilized glucose oxidase conserves its substrate specificity in the presence of a number of glucides (galactose, maltose, fructose, and saccharose) in 100 fold higher concentrations. The selectivity of glucose analysis is ensured applying a suitable potential. Interferences free glucose amperometric determination was performed at 0.00 V/SCE, in the presence of ascorbates and urates. The electrochemical quantification of enzyme inhibitors allows reaching particularly low limits of detection (10-9-10-14 mol L-1).Keywords: electrochemical biosensors, analytical characteristics, glucose oxidase, acetylcholinesterase.
Full text only in PDF format
Texto disponível em PDF
References
1. D. Thévenot, K. Toth, R. Durst, G. Wilson, Pure Appl. Chem. 71 (1999) 2333-2348. [ Links ]
2. C. Malandain, F. Fayolle, H. Bedouelle, Oil & Gas Science and Technology – Rev. IFP 60 (2005) 887-897.
3. S. Cosnier, M. Stoytcheva, A. Senillou, H. Perrot, R. Furriel, F. Leone, Anal. Chem. 77 (1999) 3692-3697.
]]> 4. M. Stoytcheva, D.Sc. Thesis work, Plovdiv University of Food Technologies, Bulgaria, 2005.5. N. Nankov, M. Stoytcheva, E. Mladenova, R. Zlatev, Bul. Soc. Chim. Belge 100 (1991) 123-128.
6. M. Stoytcheva, Bul .Soc. Chim. Belge 101 (1992) 1037-1041.
7. M. Stoytcheva, Bul. Soc. Chim. Belge 101 (1992) 1043-1046.
8. M. Stoytcheva, N. Nankov, V. Sharkova, Anal. Chim. Acta 315 (1995) 101-107.
9. S. Cosnier, F. Lambert, M. Stoytcheva, Electroanalysis 12 (2000) 356-360.
10. M. Stoytcheva, Bul. Soc. Chim. Belge 103 (1994) 147-149.
11. M. Stoytcheva, Anal. Letters 27 (1994) 3065-3080.
12. M. Stoytcheva, Electroanalysis 7 (1995) 560-562.
13. M. Stoytcheva, Electroanalysis 7 (1995) 660-662.
]]> 14. M. Stoytcheva, Electroanalysis 8 (1996) 676-679.15. M. Stoytcheva,V. Sharkova, J.P.Magnin, Electroanalysis 10 (1998) 994-998.
16. V. Sharkova, M. Stoytcheva, A. Nankov, N. Nankov, R. Zlatev, Bulgarian Chemistry and Industry 69 (1998) 132-134.
17. M. Stoytcheva, V. Sharkova, Electroanalysis 14 (2002) 1007-1010.
18. M. Stoytcheva, Electroanalysis 14 (2002) 923-927.
19. M. Stoytcheva, R. Zlatev, B. Valdez, M. Carrillo, M. Ovalle, VI Simposio Internacional: Investigación Química en la Frontera, Tijuana, Baja California, México, 2006, p. 247-248.
20. M. Stoytcheva, R. Zlatev, Electroanalysis 8 (1996) 676-679.
21. M. Stoytcheva, V. Sharkova, M. Panayotova, Anal. Chim. Acta 364 (1998) 195-201.
22. M. Stoytcheva, Annual of Sofia University of Mining and Geology 47 (2004) ІІ, 209-213.
]]> * Corresponding author. E-mail address: margarita@iing.mxl.uabc.mx ]]>