Determination of vitamins K1, K2, B6, and D3 using reduced graphene oxide fabricated using a bismuth nanoparticle embedded polypyrrole nanocomposite based optical sensor

Abstract

This research reports a simple and selective detection of vitamins K1, K2, B6, and D3 in human blood (serum/plasma) using reduced graphene oxide fabricated using the bismuth nanoparticle embedded polypyrrole nanocomposite (rGO/pPy/Bi NC) as an optical sensing material. The nanocomposite was thoroughly characterized for its functional properties using FTIR and for its morphology using SEM, AFM and TEM. The phase purity of the nanocomposite was studied using XRD diffractometry. SEM, TEM, and AFM studies confirmed the presence of nanoparticles on the polypyrrole covered sheets of rGO. The average crystallite size of GO and rGO/pPY/Bi NC was calculated using three methods using XRD analysis data. The selectivity of rGO/pPy/Bi NC is based on quenching of the optical band produced by the nanocomposite when it comes in contact with the respective vitamin in the corresponding medium. The limits of detection of vitamins K1, K2, B6, and D3 using rGO/pPY/Bi NC were found to be 0.075 ng mL⁻¹, 0.1 ng mL⁻¹, 0.12 ng mL⁻¹, and 0.15 ng mL⁻¹, respectively. However, the limits of quantification were found to be 0.29 ng mL⁻¹, 0.3 ng mL⁻¹, 0.38 ng mL⁻¹, and 0.48 ng mL⁻¹ for vitamins K1, K2, B6, and D3, respectively. The detection of vitamins in human blood (serum/plasma) with rGO/pPY/Bi NC is attributed to the novelty, simplicity, and cost-effectiveness of the sensing material. The pH sensitive rGO/pPy/Bi NC is capable of sensing four different vitamins due to the synergistic effect of rGO, Bi NPs and polypyrrole.