Facile one-step direct electrodeposition of bismuth nanowires on glassy carbon electrode for selective determination of folic acid

• BiNWs prepared through simple, fast one step electrochemical route.
• BiNWs showed more catalytic activity and sensitivity than GC towards FA reduction.
• Selective detection of FA was achieved with low limit of detection (9.53 × 10−9 mol L−1).
• Real sample analysis was successfully demonstrated using FA pharmaceutical tablets.
• BiNWs based sensor matrix is inexpensive, and more suitable for FA real application.

In the present work, we have developed a facile one step route to electrodeposition of stabilizer-free bismuth nanowires (BiNWs) on glassy carbon (GC) substrates by using a simple potentiostatic method. Formation of BiNWs on GC substrate was confirmed by field emission scanning electron microscopy (FE-SEM). The growth of BiNWs on the GC substrate was monitored by cyclic voltammetry and found that continuous in-situ generation of hydrogen bubbles during electrodeposition provides a stagnant template for the formation of BiNWs on the GC substrate. Phase-purity of the deposited BiNWs on GC substrate studied by XRD indicates no other oxide formation. The electrodeposited BiNWs on GC substrate was used for electro-reduction of folic acid (FA) and its quantitative determination in Britton-Robinson buffer of pH 4.5 solutions. The observed cyclic voltammetric reduction current of FA on BiNWs/GC is almost 15 times higher with 0.015 V less negative overpotential compared to bare GC substrate alone. This result clearly reveals the electrocatalytic activity of the deposited BiNWs. In addition, square wave voltammetry (SWV) showed a perfectly linear response in the concentration range of 1 × 10−8–15 × 10−8 mol L−1 with a correlation coefficient of 0.9956. The limit of detection (LOD) and limit of quantitation (LOQ) are determined to be 9.53 × 10−9 and 31.68 × 10−9 mol L−1 respectively. The response of the BiNWs/GC sensor matrix is not affected by any usual interference from excess concentrations of metal ions and biomolecules such as ascorbic acid, dopamine, and glucose. Further, we have also performed real sample analysis using pharmaceutical tablets containing folic acid using our BiNWs/GC in the form of recovery studies and the obtained results are found to be in good agreement with the results from high performance liquid chromatography analysis (HPLC). Based on the experimental results, it may be stated that the electrodeposited BiNWs/GC could be an ideal sensor platform for FA determination and may open up applications in biosensor design.

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