Nanostructured Diatom-ZrO2 composite as a selective and highly sensitive enzyme free electrochemical sensor for detection of methyl parathion

[Display omitted] •Novel synthesis of diatom-ZrO2 nano composites.•Selective and sensitive enzyme free electrochemical detection of methyl parathion.•Ultra-low detection limits of 54.3 pM achieved using the diatom-ZrO2 nano composites.•High sensitivity and selectivity even in the presence of other interfering ions and molecules.•Excellent recovery with Linear concentration range of 3.4 nM to 64 μM, in case of real samples. In the current work we report a simple and scalable technique for synthesis of ordered nanoporous Si-ZrO2 composite derived from the diatom Phaeodactylum tricornutum. The composite was well characterized using SEM, TEM-EDX, FTIR, TGA, BET and DLS. The diatom-ZrO2 was found to have a specific surface area of 140 m2/g, Si:Zr ratio of 1:4 and a particle size of 80 ± 2 nm. This composite was evaluated as an enzyme free electrochemical sensor towards the detection of methyl parathion (MP) and showed excellent sensing ability at extremely low detection limits of 54.3 pM and a linear concentration range of 3.4 nM to 64 μM. The diatom-ZrO2 composite was also found to be highly selective towards MP as shown by its response even in the presence of high concentrations of other interfering molecules and ions.