Pencil-drawn paper supported electrodes as simple electrochemical detectors for paper-based fluidic devices.

摘要: A simple procedure for preparing inexpensive paper-based three-electrode electrochemical cells is described here. They consist of small circular pads hydrophilic paper defined by hydrophobic barriers printed on with wax-based ink. The back face these insulated thermally laminating a polyethylene layer and working, reference counter electrodes are drawn using commercial pencil leads. At last, controlled volume sample containing supporting electrolyte was laid to soak in channels. Their performance evaluated assaying devices as both suitable recording voltammograms static samples low-cost detectors flowing systems. Voltammetric tests, conducted potassium hexacyanoferrate(II) model prototype, were also exploited identifying the brand softness graphite sticks enabling be marked lines displaying best conductivity. By taking advantage satisfactory information thus gained, tested amperometric separation ascorbic acid sunset yellow, which chosen prototype electroactive analytes because they frequently present concomitantly several food matrices, such soft drinks fruit juices. This performed planar thin chromatography microfluidic prepared patterning filter two longitudinal barriers, once again Factors affecting detection examined optimised, achieved 20 mM acetate running buffer (pH 4.5) applying potential 0.9 V. Under optimum conditions, target could separated detected within 6 min. recorded peaks well characterized good repeatability fairly sensitivity, proving that this approach indeed rapidly assembling reliable flow analysis