A disposable amperometric sensor screen printed on a nitrocellulose strip:A glucose biosensor employing lead oxide as an interference-removing agent

A new type of disposable amperometric sensor is devised by screen printing thick-film electrodes directly on a porous nitrocellulose (NC) strip. The c hromatographic NC strip is then utilized to introduce various sample pretre atment layers. As a preliminary application, a glucose biosensor based on h ydrogen peroxide detection is constructed by immobilizing glucose oxidase ( GOx) on the NC electrode strip and by formulating a strong oxidation layer (i.e., PbO2) at the sample loading area, placed below the GOx reaction band . The screen-printed PbO2 paste serves as a sample pretreatment layer that removes interference by its strong oxidizing ability. Samples applied are c arried chromatographically, via the PbO2 paste, to the GOx layer, and gluco se is catalyzed to liberate hydrogen peroxide, which is then detected at th e electrode surface. The proposed NC/PbO2 strip sensor is shown to be virtu ally insusceptible to interfering species such as acetaminophen and ascorbi c and uric acids and to exhibit good performance, in terms of the sensor-to -sensor reproducibility (standard deviation, +/-0.026-+/-0.086 mu A), the s ensitivity (slope, -0.183 mu A/mM), and the linearity (correlation coeffici ent, 0.994 in the range of 0-10 mM).