A manganese dioxide nanoparticle-bimetallic metal organic framework composite for selective and sensitive detection of vitamin D3 in human plasma

Abstract

For the first time a metal organic framework nanomaterial has been developed comprising manganese dioxide nanoparticle and iron and zinc metal ions interlinked with each other via terephthalic acid. The framework shape was identified as an elongated hexagonal nanorod (TEM) with varying functional groups (FT-IR) and diffraction patterns (XRD). The framework nanocomposite as such in aqueous acidic electrolyte solution has displayed an excellent conductivity (redox behavior) and surface excess (3.08 × 10^-8 cm^-2). Under the optimized conditions (0.1 M H₂SO₄ as electrolyte, 50 mV/s scan rate, +1.26 V (vs Ag/AgCl)), the metal organic framework coated electrode has selectively identified vitamin D₃ (VD₃) in the presence of various other interfering molecules and displayed excellent limit of detection (1.9 ng mL^-1). The developed sensor has been applied to the determination of VD₃ in extracted human plasma samples (RSD of 0.3-2.6 % and recovery of 96-102 %), and the obtained VD3 values are similar to HPLC-UV method.

Keywords: Cyclic voltammetry; Electrochemical sensor; Metal organic framework; MnO2 nanoparticle; Modified glassy carbon electrode; Plasma samples; Vitamin D3.