Electrocatalytic amperometric detection of hydroxylamine with a palladium‐modified carbon paste electrode

Abstract

Carbon paste electrodes (CPEs), modified by addition of Pd powder to the paste and electroactivation, exhibited electrocatalytic activity towards hydroxylamine. Electrogenerated palladium(0) at the electrode surface was found to be involved in the electrocatalytic oxidation of NHzOH. The electrode was employed as an amperometric detector for flow injection systems. Repeated injections (60) of hydroxylamine (5 ng) showed a relative standard deviation of 4.0%. Linear relation between the current and the analyte concentration was found between 0.1 and long of hydroxylamine. The deitection limit was 20pg NHzOH (3u). The applicability of the method to the determination of hydroxylamine in river water was investigated.

The catalytic activity of vanadium pentoxide film modified electrode on the electrochemical oxidation of hydrogen sulfide in alkaline solutions

“…This is achieved by the attachment of a catalytic species to the surface of a base electrode (bare metallic [21], metal oxides [22], glassy carbon [23], electropolymerized sensing film [24], alloys [25], etc.) which enhances its electrochemical activity.…”

Electroanalytical overview: the sensing of hydroxylamine

“…Early work on CPEs towards hydroxylamine was demonstrated by adding palladium powder into the carbon paste. 34 The electrocatalytic oxidation of hydroxylamine was discovered to involve electrogenerated palladium (0) at the electrode surface where the authors utilized a flow injection system with the CPE as an amperometric detector. A 4.0% relative standard deviation was seen after 60 times of repeated hydroxylamine injections (5 ng).…”

“…This methods was shown to sense hydroxylamine within spiked river water. 34 Other approaches have utilized various mediators to give electrocatalytic responses compared to a bare CPE, which include a magnetic bar carbon paste electrode which was modied with 1-[2,4-dihydroxy-5-(phenylazo-4-sulphonic acid) phenyl]-1-phenylmethanon (DPSPP), reduced graphene oxide (RGO) and nally with iron oxide nanoparticles, 35 as well as a CPE that was chemically modied with multiwall carbon nanotubes (MWCNTs) and p-aminophenol, 36 and a benzoylferrocene modied carbon nanotube paste electrode, 37 and last a 1,1-bis(phenyl acetyl)ferrocene modied with NiO upon CNTs modied paste electrode. 38 Of note is the work which reports the sensing of hydroxylamine and thiosulfate using a acetylferroence-cadmium oxide nanoparticles within a CPE (AF/ CdO/NPs/CPE).…”

Determination of lead and cadmium using a polycyclodextrin-modified carbon paste electrode with anodic stripping voltammetry

“…As an expected outcome, the wide field of application of the CPE is still growing mainly due to a combination of interesting features such as low manufacturing costs offset by a wide potential window, ease of preparation and a surface that is modifiable without having to use other contaminating chemical species; these have turned them into selective, versatile and renewable analytical devices [6]. Modification of the CPE electrodes can be effected by means of a mix of electroactive compounds [4,5,7,8,9,10], by adsorption or electrodeposition [11,12]. To get a response similar to that of the HDME a CPE has been modified with Hg electrodeposits to determine Pb(II) obtaining low detection limits (2.5×10 -9 M with a t d =10 min) [12,13,14,15].…”