The effect of structure on poly(quinone) systems for amperometric glucose sensors

Abstract

2,5-Etheramino-p-benzoquinone I, poly(2,5-etheramino-p-benzoquinone)s IIa–c ( x = 3, 6 and 33), poly(2,5-ω,ω′-hexamethylenediamino-p-benzoquinone) IV and poly(3,6-etheramino-o-benzoquinone) V (x = 6) (x is the number of propylene oxide repeating units) were synthesized and their efficiencies as electron relay systems for amperometric glucose sensors were investigated and compared. Cyclic voltammetry and steady state potential measurements showed that the quinone monomer and polymers efficiently mediated electron transfer from reduced glucose oxidase to a conventional carbon paste electrode. Sensors constructed with 2,5-etheramino-p-benzoquinone showed higher efficiency than those constructed with polymeric systems. Among the poly(2,5-etheramino-p-benzoquinone)s, the length of the propylene oxide chain between quinone moieties was found to be critical for electron relay efficiency. Sensors constructed from polymers with shorter propylene oxide chains between the quinone moieties demonstrated greater efficiency than those constructed from polymers with longer propylene oxide chains (x = 3 > 6 ⪢ 33). The sensor stability was investigated using sensors containing monomeric quinone compound I, non-crosslinked polymer IIb and crosslinked polymer VI. The sensors with crosslinked polymer were the most stable and maintained their efficiency over 50 days.