Organoclay-modified electrodes: preparation, characterization and recent electroanalytical applications

Abstract

Amperometric sensors dedicated to the determination of pollutants and other compounds of interest face daily a great challenge: the development of sensitive, reproducible and low-cost devices allowing fast analyses. This review deals with the beneficial role and application of organoclays exploited as sensing materials in various fields of electroanalysis, for the past 15 years (period 2000-2014). After a description of different preparation methods leading to clay minerals chemically modified by organic compounds, the common methods used for their characterization are exposed; then, their application as electrode modifiers is described, covering several approaches that were developed to enhance either the sensitivity or the selectivity of the indexed organoclay-based sensors. Finally, a brief description of voltammetric methods frequently used for electroanalytical purposes is given, followed by an update of recent and salient results achieved for the detection of inorganic and organic electroactive compounds or ions.

Nanohybrid materials from amine functionalization of sepiolite: Preparation, characterization and application as electrode modifiers for the electroanalytical detection of heavy metal ions

“…It is followed by two other steps in which sepiolite losses half of the coordinated water at 290°C while the remaining part of this water is removed around 520°C. The last step occurs at 831°C and is relate to the departure of water related to structural OH, that is to the endothermal dehydroxylation of sepiolite leading to the destruction of its structure [26,43,44]. water do not undergo change, suggesting that the oorganosilane molecules are not incorporated into the channels of sepiolite but have reacted with the external Si-OH groups found on its surface [4] as expected.…”

“…Sepiolite with the half-unit cell chemical formula Mg 8 Si 12 O 30 (OH) 4 (H 2 O) 4 .8H 2 O is a fibrous porous hydrated magnesium silicate [26,43,44]. Structurally, it is made up of blocks and channels extending in the fiber direction (c-axis).…”

Evaluation of the degradation of acetaminophen by the filamentous fungus Scedosporium dehoogii using carbon-based modified electrodes

“…The resort to electrochemical methods for the determination of biological compounds in environmental analysis is also because they are reagentless and require simple operational procedures [28]. Moreover, they can allow quite fast analyses leading to experimental data obtained in real time, with a high selectivity and sensitivity [28][29][30]. In that field, chemically modified electrodes usually play a key role as sensing devices.…”

“…Some recent reports on the detection of APAP by means of carbon-based electrodes include the use of glassy carbon coated by various modifiers [32,33] and mainly the exploitation of chemically modified carbon paste electrodes [34][35][36][37][38][39][40]. In the special case of stripping voltammetry exploiting these modified electrodes, typical limits of detection are between 10 −5 and 10 −10 M [30,[34][35][36][37]. The previously mentioned studies reveal that the design of simple, sensitive, and fast procedures for the detection of APAP is currently an active field of research.…”

“…In that field, chemically modified electrodes usually play a key role as sensing devices. Of particular interest are carbon-based modified electrodes that are easy to prepare, inexpensive, and generally give rise to reproducible signals [30,31]. Some recent reports on the detection of APAP by means of carbon-based electrodes include the use of glassy carbon coated by various modifiers [32,33] and mainly the exploitation of chemically modified carbon paste electrodes [34][35][36][37][38][39][40].…”