In situ synthesis of thulium(III) hexacyanoferrate(II) nanoparticles and its application for glucose detection

Thulium hexacyanoferrate (TmHCF) nanoparticles (NPs) were in situ synthesized within the chitosan film on the electrode surface by a biocatalyzed reaction. The properties of the obtained nanoparticles are characterized with scanning electron microscope (SEM) and energy-dispersive X-ray (EDX). The optimized conditions for the formation of TmHCF NPs were 16 mM Fe(CN)₆³⁻ and 1.5 mM Tm³⁺ with an accumulation time of 20 min. Based on process of in situ synthesis of TmHCF NPs, a novel biosensor for glucose was designed, and there is a linear relationship between the current response of TmHCF NPs and glucose concentration. The linear range for glucose detection was 0.02–0.4 mM (r = 0.9975, n = 5) and 0.4–13.6 mM (r = 0.9935, n = 10) and the detection limit was 6 μM at a signal-to-noise ratio of 3.