دانلود مقاله با موضوع خطاهای تحلیلی در حسگرهای زیستی با استفاده از مرجع ترکیبی ضد/شبه الکترودها
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موضوع انگلیسی:Analytical errors in biosensors employing combined counter/pseudoreference
electrodes
بخشی از متن:The performance of the reference electrode is sometimes overlooked in the development of newelectrochemical
biosensors, which may result in a significant reduction in function even under standard operating conditions.
This paper investigates the worst-case analytical errors, mainly addressed through finite element modelling
and further supported by experimental data. The specific case of a two-electrodemediated amperometric biosensor
utilizing Ag/AgCl as a combined counter and pseudo-reference electrode was modelled numerically. The reference
electrodewas found to shift 5mV for every 20mMchange in analyte concentration. In addition, a gradual
increasewith time was observed. This deviation in reference potential resulted in a lowering of the current magnitude
with increasing analyte concentration due to the operating potential of the working electrode being
shifted closer to the reversible potential of the electrode reaction. The analytical deviation was measured to
14% away from the ideal value following a titration curve from 5 mM to 25 mM over 150 s. The combined
counter/pseudo-reference electrode was further studied experimentally during current load in a ferro/ferricyanide
mediator system and compared to that of using separate counter and pseudo-reference electrodes. A linear
7 mV μA−1 cm−2 potential shift-to-current relation was deduced for the former case, whereas the potential
remained stable when separate reference and counter electrodes were used
