Reply to "Comment on intrazeolite electron transport mechanism". The importance of the manner to prepare zeolite-modified electrodes

Carbon ceramic electrode incorporated with zeolite ZSM-5 for determination of Piroxicam

“…Currently, one of the most robust ZMEs is a zeolite-containing carbon composite of a cross-linked copolymer of styrene and divinylbenzene developed by Shaw and Creasy [17]. There has been a discussion in the literature concerning the different electrochemical behavior attributed to the different morphologies of the zeolite layers [18,19] and experimental protocol [20,21] for making ZMEs. The main problem of ZMEs, particularly for electroanalysis, is the lack of reproducibility [12], due to the hetereogeneous nature of most ZMEs and the difficulty of surface renewal.…”

Electro- and magneto-electrochemistry of zeolite Y- and MCM-41-associated bipyrylium ion

“…The mechanism of charge transfer at zeolite-modified electrodes, however, has been the subject of discussion [3][4][5][6]. Three basic models, extrazeolitic, intrazeolitic, and surface-mediated have been proposed [7,8].…”

10.1007/s10809-008-2014-3

“…In the past, fundamental studies involving ZMEs based on ionexchange equilibrium occurring at zeolite particles were not widespread [11,12]. Baker et al [8,[13][14][15] focused on the electron-transfer mechanisms and ion-exchange reactions (cation-site effects, intracrystalline cation exchange, kinetics), especially for partial-exchange zeolites embedded in a polystyrene film-coated on solid electrodes, while Calzaferri's group proposed intrazeolite ion and elec-tron-transport mechanisms for dense zeolite monograin layers on substrate electrodes [16,17]. Baker et al [8,[13][14][15] focused on the electron-transfer mechanisms and ion-exchange reactions (cation-site effects, intracrystalline cation exchange, kinetics), especially for partial-exchange zeolites embedded in a polystyrene film-coated on solid electrodes, while Calzaferri's group proposed intrazeolite ion and elec-tron-transport mechanisms for dense zeolite monograin layers on substrate electrodes [16,17].…”

“…Recently, intrazeolite effects observed with ZMEs were reported [8,10]. All previously described fundamental investigations of ZMEs were performed using preexchanged (completely or not) zeolite particles, where the electroactive materials were initially located in the bulk zeolite, not from an external solution, which should be done when using ZMEs an ion-exchange preconcentrating system in order to detect an analyte electrochemically [11,17]. Such studies are very informative owing to the demonstrated ability of ZMEs to distinguish electroactive species on the basis of their ion-exchange sites in the zeolite framework; however, they are not directed towards analytical applications of ZMEs with the aim of preconcentrating electroactive cations before their electrochemical sensing.…”