Bimetallic-based food sensors for meat spoilage: Effects of the accepting metallic unit in Fe(II)─C≡N─M_A (M_A ≡ Pt(II) or Au(I)) on device selectivity and sensitivity

Technologies for monitoring meat spoilage are important to ensuring consumer safety. As dimethyl sulfide (DMS) is a reliable marker for meat freshness, sensitive and selective DMS sensors are of great interest. Herein, two trinuclear cyano-bridged bimetallic donor–acceptor ensembles, Fe^II(bpy)₂(CN)₂–[Pt^II(DMSO)Cl₂]₂ (1) and Fe^II(bpy)₂(CN)₂–[Au^ICl]₂, were synthesized, and corresponding solid-supported sensors were fabricated to determine the effect of the acceptor metal (M_A) on DMS detection. Changing M_A from Au^I to Pt^II improved the sensitivity and selectivity owing to changes in the relative thermodynamic stabilities of the complex and M_A–DMS adduct. When applied to real meat samples, 1 exhibited a linear spectroscopic response to DMS, even in the presence of interfering compounds, with a method detection limit of 1.0 ppm. The total bacteria count and gas chromatography–mass spectrometry results revealed that the spectroscopic signal generated by 1 correlated with the microbial growth level and DMS concentration during meat spoilage. Copyright © 2019 Elsevier Ltd. All rights reserved.