TY - JOUR
T1 - Effects of architecture and surface chemistry of three-dimensionally ordered macroporous carbon solid contacts on performance of ion-selective electrodes
AU - Fierke, Melissa A.
AU - Lai, Chun Ze
AU - Bühlmann, Philippe
AU - Stein, Andreas
PY - 2010/1/15
Y1 - 2010/1/15
N2 - The effects of the architecture and surface chemistry of three-dimensionally ordered macroporous (3DOM) carbon solid contacts on the properties of ion-selective electrodes (ISEs) were examined. Infiltration of the plasticized poly(vinyl chloride) (PVC) membrane into the pores of the carbon created a large interfacial area between the sensing membrane and the solid contact, as shown by cryo-scanning electron microscopy (cryo-SEM) and elemental analysis. This large interfacial area, along with the high capacitance of the 3DOM carbon solid contacts (as determined by cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectros- copy) results in an excellent long-term stability of the potentiometric response, with drifts as low as 11.7 μV/h. The comparison of 3DOM carbon solid contacts with an untemplated carbon solid contact shows that the pore structure is an essential feature for the excellent electrode performance. However, the surface chemistry of the 3DOM carbon cannot be ignored. While there is no evidence for an aqueous layer forming between the sensing membrane and unoxidized 3DOM carbon, electrodes based on oxidized 3DOM carbon exhibit potentiometric responses with the typical hysteresis indicative of a water layer. A comparison of the different techniques to characterize the solid contacts confirms that constant-current charge-discharge experiments offer an intriguing approach to assess the long-term stability of solid-contact ISEs but shows that their results need to be interpreted with care.
AB - The effects of the architecture and surface chemistry of three-dimensionally ordered macroporous (3DOM) carbon solid contacts on the properties of ion-selective electrodes (ISEs) were examined. Infiltration of the plasticized poly(vinyl chloride) (PVC) membrane into the pores of the carbon created a large interfacial area between the sensing membrane and the solid contact, as shown by cryo-scanning electron microscopy (cryo-SEM) and elemental analysis. This large interfacial area, along with the high capacitance of the 3DOM carbon solid contacts (as determined by cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectros- copy) results in an excellent long-term stability of the potentiometric response, with drifts as low as 11.7 μV/h. The comparison of 3DOM carbon solid contacts with an untemplated carbon solid contact shows that the pore structure is an essential feature for the excellent electrode performance. However, the surface chemistry of the 3DOM carbon cannot be ignored. While there is no evidence for an aqueous layer forming between the sensing membrane and unoxidized 3DOM carbon, electrodes based on oxidized 3DOM carbon exhibit potentiometric responses with the typical hysteresis indicative of a water layer. A comparison of the different techniques to characterize the solid contacts confirms that constant-current charge-discharge experiments offer an intriguing approach to assess the long-term stability of solid-contact ISEs but shows that their results need to be interpreted with care.
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U2 - 10.1021/ac902222n
DO - 10.1021/ac902222n
M3 - Article
C2 - 20000696
AN - SCOPUS:75649130092
SN - 0003-2700
VL - 82
SP - 680
EP - 688
JO - Analytical Chemistry
JF - Analytical Chemistry
IS - 2
ER -