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

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 H 2 SO 4 as electrolyte, 50 mV/s scan rate, +1.26 V (vs Ag/AgCl)), the metal organic framework coated electrode has selectively identified vitamin D 3 (VD 3 ) 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 VD 3 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. Graphical abstract