Rational design of platinum assimilated 3-D zinc cobalt oxide flowers for the electrochemical detection of caffeine in beverage and energy drink

In this work, platinum nanoparticles (Pt) decorated on a spinel group, zinc cobalt oxide (ZnCo₂O₄) 3-D flower was intended to detect caffeine electrochemical sensor. Pt particles were used to enhance the performance of hydrothermally prepared 3-D ZnCo₂O₄ flower. So Pt nanoparticles were decorated on each thin nanosheet of self-assembled 3-D flower-like ZnCo₂O₄. The thin transparent nanosheet of the ZnCo₂O₄ flower will benefit electrochemical sensors by simplifying its ion exchange. Therefore, Pt@ZnCo₂O₄ shows an excellent electrochemical conductivity, which promotes the caffeine-based sensor's rapid electrochemical oxidation. Using amperometric i-t at an applied potential of 1.45 V, Pt@ZnCo₂O₄ modified electrode shows widespread of two linear ranges (0.05 to 265.55 μM and 295.55 to 757.55 μM) with a low detection limit (0.0114 and 0.01657 μM) and high sensitivity (3.419 and 1.862 μA μM⁻¹ cm⁻²). Moreover, good results were obtained for the real-time detection of caffeine in sugar-free cola beverage and energy drink samples. Henceforth, the developed method could be an ideal way to detect caffeine in real samples.