Preparation of Ru–Pt bimetallic monolayer on nanoporous gold film electrode and its application as an ultrasensitive sensor for determination of methionine

Abstract

We report here the fabrication of ruthenium/platinum (RuPt) bimetallic monolayer coated on a nanoporous gold film electrode (RuPtNPGF) by underpotential deposition of copper (UPD) with the Cu layer then replaced spontaneously by Ru and Pt. The present method could provide a very low RuPt-loading electrode and the results demonstrated that ultra thin RuPt coating behaved efficiently as a bimetallic nanostructure RuPt for electrocatalytic oxidation of methionine. The structure and morphology of the catalyst were defined by using energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM), respectively. The RuPtNPGF electrode displayed good performance along with low working potential, high selectivity, and a low detection limit for the oxidation of methionine. Whereas at the surface of the bare electrode a redox peak for methionine cannot be observed, a sharp anodic peak at a potential of 0.73 V (vs. Ag/AgCl) in pH ¼ 7.0 is obtained using the prepared RuPtNPGF electrode. Under optimized conditions differential pulse voltammetry (DPV) of methionine showed two linear ranges for the determination of methionine: 6-105 nmol L À1 and 3-102 mmol L À1 with a detection limit of 2 nmol L À1 . Finally, the proposed sensor was successfully applied for the determination of methionine in human urine, with satisfactory results.

Electrochemical Amino Acid Sensing: A Review on Challenges and Achievements

“…Noble metals and their alloys, as expected, are the main modifiers used in electrochemical methionine sensors [ 181 , 182 , 183 , 184 ]. These noble metals are exploited either in monometallic form [ 181 , 184 ] or as a bimetallic compound, e.g., Ru/Pt [ 182 ] and Ag/Au [ 183 ].…”

“…Noble metals and their alloys, as expected, are the main modifiers used in electrochemical methionine sensors [ 181 , 182 , 183 , 184 ]. These noble metals are exploited either in monometallic form [ 181 , 184 ] or as a bimetallic compound, e.g., Ru/Pt [ 182 ] and Ag/Au [ 183 ]. Bimetallic modifiers are expected to surpass their monometallic counterparts through improving the effective surface area, electron transfer rate, biocompatibility, electrocatalytic activity and invulnerability against interfering species and/or intermediate by-products of electrochemical reactions.…”

“…Bimetallic modifiers are expected to surpass their monometallic counterparts through improving the effective surface area, electron transfer rate, biocompatibility, electrocatalytic activity and invulnerability against interfering species and/or intermediate by-products of electrochemical reactions. In a study, Tavakkoli et al [ 182 ] deposited a bimetallic monolayer of ruthenium/platinum (Ru/Pt) on gold electrodes. For this, first, the underpotential deposition of copper on gold electrode was carried out and followed by the replacement of this copper layer with Ru and Pt at open-circuit potential.…”

Carbon Nano Onions–Polystyrene Composite for Sensing S-Containing Amino Acids

“…Moreover, a carbon electrode, modified by using cyclotricatechylene, was used for the selective detection of Cys [27]. Other nanomaterials, such as ZnO nanorods, modified the carbon paste electrode [28], while the graphene-oxide modified screen printed carbon electrode [29] and Ru-Pt bimetallic monolayer on a nano-porous gold film electrode [30] were used to detect Met. Furthermore, different skills, such as those of the glucose/O 2 -based biofuel cell [31], the fluorescence quenching process [32] and the organic field-effect transistor [33], are used to detect Cys and Met.…”

Development of specificl-methionine sensors by FRET-based protein engineering

“…20 Because of the biochemical importance of L-Met, many L-Met sensors have been reported. [21][22][23][24][25][26][27] Although each reported method has its advantages and is useful in a specic application, none of the methods is able to specically measure L-Met concentration in a complex mixture such as blood serum. In this study, a protein sensor highly specic for L-Met was developed by engineering a natural Met-binding protein and using a genetic code expansion technique for the incorporation of a uorescent unnatural amino acid (UAA) to sense the target molecule via uorescence resonance energy transfer (FRET).…”