Real-time measurement of glucose using chrono-impedance technique on a second generation biosensor

MAYORGA, CARMEN CLOTILDE; TREO, ERNESTO FEDERICO; MADRID, ROSSANA ELENA; FELICE, CARMELO JOSÉ

BIOSENSORS & BIOELECTRONICS

ELSEVIER ADVANCED TECHNOLOGY

Lugar: Amsterdam; Año: 2011 vol. 29 p. 200 - 203

0956-5663

Chrono-impedance technique (CIT) was implemented as a new transduction method for real time measurement of glucose in a biosensor system based in carbon paste (CP)/Ferrocene (FC)/glucose oxidase (GOx). The system presents high selectivity because the optimal stimulation signal composed by a 165 mV DC potential and 50 mVRMS AC signal at 0.4 Hz was used. The low DC potential used decreased the interfering species effect and the biosensor showed a linear impedance response toward glucose detection at concentrations from 0 mM to 20 mM,with 0.9853 and 0.9945 correlation coefficient for impedance module (|Z|) and phase (˚), respectively. The results of quadruplicate sets reveal the high repeatability and reproducibility of the measurements with a relative standard deviation (RSD) less than 10%. CIT presented good accuracy (within 10% of the actual value) and precision did not exceed 15% of RSD for highconcentration values and 20% for the low concentration ones. In addition, a high correlation coefficient (R2 = 0.9954) between chrono-impedance and colorimetric methods was obtained. On the other hand, when two samples prepared at the same conditions were measured in parallel with both methods (the measurement was repeated four times), it should be noticed that student’s t-test produced no difference between the two mentioned methods (p = 1). The biosensor system hereby presented is highly specific to glucose detection and shows a better linear range than the one reported on the previous article.