A novel biosensor for reduced l-glutathione based on cobalt phthalocyaninetetrasulfonate-intercalated layered double hydroxide modified glassy carbon electrodes

A cobalt phthalocyaninetetrasulfonate (CoTsPc) intercalated Zn–Al layered double hydroxide (ZnAl–CoTsPc–LDH) has been prepared and used as a modified electrode material for electrocatalytic oxidation and detection of an important biological molecule, reduced l-glutathione (GSH). As the intercalated structure can efficiently immobilize the CoTsPc and inhibit its aggregation, a ZnAl–CoTsPc–LDH modified glassy carbon (GC) electrode exhibited significantly enhanced electrocatalytic activity and stability towards GSH compared with GC electrodes modified with pure CoTsPc or CoTsPc adsorbed on the outer surfaces of Zn–Al layered double hydroxide (CoTsPc/ZnAl–LDH). At physiological pH, the ZnAl–CoTsPc–LDH modified GC electrode showed a wide linear range from 1 to 818 μM and low detection limit of 0.2 μM for GSH determination. Our results show that intercalation of cobalt phthalocyanine complexes into the interlayer galleries of a LDH host is an effective way to improve the electrocatalytic activity and stability of cobalt phthalocyanine modified electrodes, and may have potential applications in fields such as biosensors, biofuel cells, and bioelectronic devices.