Ni–Fe PBA hollow nanocubes as efficient electrode materials for highly sensitive detection of guanine and hydrogen peroxide in human whole saliva

A sensor for the determination of guanine (G) and hydrogen peroxide (H 2 O 2 ) is developed based on Ni–Fe Prussian blue analogues hollow nanocubes (Ni–Fe PBA HNCs) for the first time. As a remarkable redox probe towards G and H 2 O 2 oxidation , Ni–Fe PBA HNCs exhibit a series of predominant sensing performances as follows: lower limit of detection, broader linear range and higher selectivity due to the homogeneous hollow structure, high specific surface and the enhanced electron transfer ability of Ni–Fe PBA HNCs. As a G sensor, it exhibits a wide linear range (0.05–4.0 mM) and a low detection limit of 0.0104 μM (S/N = 3). As a H 2 O 2 sensor, the Ni–Fe PBA HNCs show superior sensing performances with a low detection limit of 0.291 μM (S/N = 3) and a wide detection range of 0.1–20 mM. By cause of these advantages, the real-time detection of G and H 2 O 2 in human saliva are triumphantly accomplishment, indicating the applicability of Ni–Fe PBA HNCs.