A non-enzymatic electrochemical approach for l-lactic acid sensor development based on CuO·MWCNT nanocomposites modified with a Nafion matrix

Abstract

Copper oxide decorated multi-walled carbon nanotube nanocomposites (CuO·MWCNT NCs) were prepared using a simple wet-chemical technique in basic medium. The CuO·MWCNT NCs were examined by using various analytical techniques, for example ultraviolet-visible spectroscopy (UV-visible), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). An L-lactic acid sensor was developed with modification of a thin layer of nanocomposite onto a flat glassy carbon electrode (GCE, surface area = 0.0316 cm²). Analytical sensor performances for example sensitivity, limit of detection (LOD), limit of quantification (LOQ), linear dynamic range (LDR), durability, interference effect examination, and real sample analysis of the synthesized L-lactic acid sensor were achieved through a dependable current–voltage procedure. The calibration curve of the GCE/CuO·MWCNT NCs/NAF sensor was linear (R² = 0.9891) over an extensive range of L-lactic acid concentrations (100.0 pM–100.0 mM). The sensitivity (633.0 pA μM⁻¹ cm⁻²), LOD (≈88.5 pM), LOQ (295.0 mM), and LDR (100.0 pM–10.0 mM) of the L-lactic acid sensor were determined correspondingly from the calibration curve. Preparation of CuO·MWCNT NCs using a wet-chemical procedure is excellent progression for the expansion of nanocomposite based sensor development in support of enzyme-free discovery of bio-molecules in healthcare fields. This expected GCE/CuO·MWCNT NCs/NAF sensor was applied for the specific identification of L-lactic acid in real serum samples and provided reasonable and acceptable results.