A combined liquid three-phase micro-extraction and differential pulse voltammetric method for preconcentration and detection of ultra-trace amounts of buprenorphine using a modified pencil electrode

Recent Advances in Nanomaterial‐Modified Pencil Graphite Electrodes for Electroanalysis

“…In 2013, Ensafi et al. 2013 42 prepared MWCNT‐modified PGEs (MWCNT/PGEs) via physical adsorption. The MWCNT/PGE nanocomposite electrode was coupled to a PTFE membrane.…”

“…Recent studies have focused on surface modifications with nanocomposite materials that incorporate both polymers and nanomaterials, such as polypyrrole‐MWCNT modified PGE 40, MWCNT‐chitosen‐PGE 41, polytetrafluoroethylene (PTFE) membrane‐MWCNT‐modified PGE 42, molecularly imprinted polymer (MIP)‐MWCNT‐PGE 43, AgNP‐polyaniline‐PGE 44, or dual‐ion imprinted polymer‐containing nanohybrids 45. The use of both polymers and nanomaterials as surface modifiers relies on two principles: First, the catalytic activities of both the electroactive polymers and the nanomaterials in the preparation of sensitive and specific electrode surfaces provide superior results compared to the results obtained using only the individual materials.…”

Recent Developments in Voltammetric Analysis of Pharmaceuticals Using Disposable Pencil Graphite Electrodes

“…Drop coating was applied to produce Mo 5 O 8 /PGE [34], Trypan blue-modified PGEs [44], different CNT-modified PGEs [47,57,58,68], or PGEs covered with various modifiers [41,49,62,65,135]. After that, the modified PGE was dried either in air [35,48,52,66,68,69,90,136] or in other well-established conditions (e.g., in a desiccator [50] or at a certain temperature [125,137]). The substrate could be either inactivated or electrochemically treated (ET) PGEs (Table 3).…”

“…Liquid three-phase microextraction (LPME) consists of analyte transfer from the aqueous donor phase to a thin layer of a proper organic solvent immobilized within a porous membrane, followed by the re-extraction of it into a smaller volume of an aqueous acceptor phase. A polytetrafluoroethylene (PTFE) membrane impregnated with propyl benzoate was used to transport buprenorphine from the sample (aqueous phase) to the acceptor phase, and a MWCNTs/ET-PGE was used to study the electrochemical behavior of this pharmaceutical and to quantify it by DPV [137]. A similar extraction-electrochemical set-up was described by the same authors for insulin determination.…”

A carbon needle microelectrode decorated with TiO 2 nanosheets dominated by reactive facets as a highly electrocatalytic sensing element

“…The TiO 2 morphology consisted of nanosheets, which indicates that the roughness and surface areato-volume ratio of the modified electrode were considerably greater than those of the unmodified electrode. Modification was beneficial for improving catalytic activity and sensor sensitivity of the electrochemical sensor [45]. Moreover, the detailed morphology of as-prepared TiO 2 -CNE was monitored via HRTEM analysis, as shown in Fig.…”