Abstract
A highly conductive thin film composite based on silver nanoparticles (AgNPs) and malic acid (MA) was deposited on glassy carbon electrode (GCE) for the selective and sensitive electrochemical sensing of trichloroacetic acid (TCA). The casting solution containing MA functionalized AgNPs was employed as a precursor for the thermal deposition of the AgNPs integrated MA thin film composite onto the GCE surface. The uniform coverage of AgNPs within the thin film composite at GCE was obtained by field emission scanning electron microscopy (FESEM). A significantly high charge transfer resistance of the modified electrode (85.7 Ω for AgNPs-MA/GCE in 2 mM [Fe(CN)6]3-/4- at a bias of +0.235 V as compared to bare GCE (38.01 Ω) verified the optimum coating of AgNPs-MA composite at the surface of the electrode. The AgNPs-MA composite deposited GCE revealed substantial electrocatalytic activity toward TCA reduction with significantly enhanced reduction current. The novel electrode manifested a linear square wave voltammetric (SWV) response over the concentration ranges of 0.1–2 (R2 = 0.9953) and 4-100 μM (R2 = 0.9969) with a limit of detection (LOD) and limit of quantification (LOQ) of 30 nM and 92.5 nM, respectively. The modified electrode exhibited an excellent long-term stability (30 days) with the retention of >95% of initial current. The selectivity of the proposed electrode for the determination of TCA was examined in the presence of dichloroacetic acid (DCA) and monochloroacetic acid (MCA) with the retention of high recovery percentages.
Schematic representation of reduction of TCA and its immediate reduction products at AgNPs-MA/GCE. [Display omitted]
•AgNPs and malic acid thin film nanocomposite based modified GCE is constructed.•The Analytical utility of the modified electrode in one-step assay was demonstrated for TCA detection.•An excellent LOD (30 nM) with good linear dynamic range (0.1–2 μM) were achieved.•Minimum interference and discrimination of DCA and MCA towards TCA were achieved.•The proposed sensor is easy to use, stable and has great potential in resource limiting countries.